| 1914 | August 15 | German troops based in Ruanda-Urundi cut the telegraph line and bombard Belgian Congo towns along Lake Tanganyika. |
| August 22 | A German gunboat opens fire on the Port of Albertville on the Belgian Congo shore of Lake Tanganyika. |
| December 14 | Belgian forces recapture Ngoma, Congo and capture Kissenji on Lake Kivu in the German East African district of Ruanda. Kissenji's fortress remains in German hands. |
| 1915 | May 15 | Belgian forces overrun the German fort at Kissenji on Lake Kivu and occupy the German East African districts of Ruanda and Urundi. |
| November 30 | King Mutaga IV Mbikije of Urundi is dies afther a fight with his brother Bangura who was surprised while courting one of the kings two wives. |
| December 16 | Three year old Mwambutsa IV Bangilicenge begins a 51 year reign as King of Urundi. |
| 1916 | April 18 | General Charles Tombeur launches a Belgian offensive against German East Africa with an attack force composed of two groups each with two regiments. Colonel Philippe Molitor commands the Northern Brigade and Lieutenant Frederik Olsen the Southern Brigade. |
| | Colonel Olsen's Southern Brigade occupies Gombo Island at the south end of Lake Kivu. |
| April 19 | Colonel Molitor's Northern Brigade captures Shyangugu, Ruanda and turns north for a march on Kigali. |
| May 6 | Ruanda's capital, Kigali, falls to the Belgians. |
| | German forces commanded by Captain von Languenn put up a stiff resistance but a forced to withdraw from Urundi by the superior numbers of Colonel Olsen's Belgian brigade. |
| May 19 | Belgian troops commanded by Major Muller occupy Nyanza, Urundi on Lake Tanganyika. |
| June 6 | Urundi's capital, Usumbura, falls to Belgian forces commanded by Colonel Thomas. |
| June 17 | The Belgian conquest of Ruanda and Urundi is completed with capture of Kitega, Urundi. The Belgians press on with the campaign in German East Africa. Colonel Molitor's brigade captures Biharamuro then Mwanza. Colonel Moulaert's forces occupy Karema. The March on Tabora begins in three columns. |
| June 27 | Belgian Military Residents, Edouard van den Eede for Urundi and Major Gustave Stevens for Ruanda, are appointed to direct the administration of occupied German East Africa. They issue a series of edicts covering military discipline and public order along with regulations on alcoholic beverages, military requisitions, use of military transport for commercial purposes and vagrancy. |
| July 29 | Belgian forces occupy Kigoma and Ujiji in German East Africa. |
| September 19 | Tabora falls to the Belgians. Belgian and British forces complete the conquest of German East Africa although German commander General von Lettow Vorbeck continues to wage a guerilla campaign until after the 1918 armistice. |
| 1917 | February 1 | Belgium installs a Royal Commissioner at Kigoma and divides its zone of occupation in German East Africa into four districts: the Residency of Ruanda, the Residency of Urundi, the Territory of Usui and the District of Ujiji. Tabora is ceded to the British. Most Belgian Congolese troops are sent home leaving only a small occupation force behind. Lieutenant Colonel Armand Christophe Huyghe is appointed Commander in Chief of the Eastern Forces of the Force Publique. |
| April 30 | Gerard Francois Declerck is appointed Military Resident for Ruanda. |
| June | Belgian forces launch a new offensive against General von Lettow Vorbeck's guerrilla's in German East Africa. |
| October | Belgian forces occupy the Mahenge District of German East Africa. Major Leopold Eugene Bataille is appointed Commander of the Occupation Force in East Africa including Mahenge. |
| 1918 | January | Belgium appoints the first civil residents: Pierre Ryckmans for Urundi and Edouard van den Eede for Ruanda. |
| May 30 | Belgian representative Pierre Ortz and British Secretary of State for Colonies Lord Milner sign a convention under which the Residencies of Ruand and Urundi are given to Belgium and the Territory of Usui along with the District of Ujiji are ceded to Great Britain. |
| 1919 | June 28 | Treaty of Versailles is signed. Germany surrenders its rights in East Africa including the districts of Ruanda and Urundi. |
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| 1920 | | Vocational institutes are established to train medical assistants at Gitega, veterinarians at Nyanza and agricultural agents at Kitega. |
| 1921 | March 22 | Belgium transfers control of former German East African districts of Usui and Ujiji to the British mandate of Tanganyika. Gisaka, Ruanda and Bugufi, Urundi are also ceded to Tanganyika to allow construction of the Cape to Cairo Railway entirely through British territory. Belgium is granted extraterritorial concessions at Kigoma and Dar es Salam along with special facilities on the railway linking those towns and rights of free passage for goods going to or from the Belgian Congo. King Yuhi V Musinga of Ruanda lodges a vigorous protest over the loss of 1/4th of his domain but to no avail. Gisaka is retroceded to Ruand at a later date but Bugufi is fully integrated within Tanganyika. |
| 1922 | July 20 | The League of Nations confirms Belgium's mandate over Ruanda-Urundi. |
| During the Year | The Roman Catholic Vicarat Apostolic of Urundi is established. Support for missionary work, Protestant under the Germans, is lent to Catholics under the Belgian administration which entrust the educational sector to them. Kiranga the traditional native religion and basis of the theocratic power of the monarchy is suppressed and those who continue to practice it loose social standing. Islam is restricted by prohibition of Swahili in the schools and permits to build mosques are limited. |
| 1923 | August 31 | The League of Nations reaffirms its decision to confer a mandate over Ruanda-Urundi to Belgium. |
| 1924 | October 20 | Alfred Marzorati is appointed Royal Commissioner for the Mandate of Ruanda-Urundi. |
| October 24 | A Belgian law is promulgated to accept the League of Nations mandate to civilize and provide for the well being of the inhabitants and undertake the development of Ruanda-Urundi. The statute recongizes Belgium's obligation to govern the territory on a different basis than that of a colony and to report on its progress to the League's Standing Committee on Mandates. |
| 1925 | August 21 | The Belgian Parliament enacts legislation to unite Ruanda-Urundi with the Belgian Congo for administrative purposes. |
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| 1926 | March 1 | Ruanda-Urundi is administratively united with the Belgian Congo. Decrees and legislative ordinances issued by the Governor General of the Congo without specific reference to Ruanda-Urundi are only applied to the territory by executive ordinance of the mandate's Vice Governor General. |
| | Louis Joseph Postiaux is appointed Vice Governor General for Ruanda-Urundi. |
| During the Year | The Ruandan monarchy is made hereditary. The power of the Tutsi aristocracy is solidified. |
| 1929 | | The Groupe Scolaire d'Astrida is established to provide secondary education to aspiring civil servants, chiefs, medical and veterinary assistants and farmers. |
| 1930s | The colonial administration urges the chiefs to create markets in their districts. Internal trade is dominated by Indians, Arabs and Greeks selling imported vehicles, fuel, cigarettes, machinery, farm implements and clothing and exporting coffee, vegetables, cattle and hides. Prices in rural markets are controlled. |
| 1931 | November 12 | King Yuhi V Musinga of Ruanda is exiled to Moba in the Belgian Congo for resisting the encroachments of the Belgian administration and the Catholic missionaries. |
| November 16 | Mutara III Rudahigwa, son of exiled King Yuhi V Musinga, is crowned King of Ruanda, The Belgians believe the 20 year old will be more docile. |
| During the Year | The Belgians require every able bodied man in the mandate to cultivate at least 35 food plants. Resistance to the new agricultural regime is gradually overcome and wheat, potatoes and soy are popularized by agronomists at the Gisozi research station. Commercial crops grown for export, i.e. coffee, cotton and palm oil continue to dominate the economy. |
| 1934-1935 | A census of able bodied Ruandan men is conducted at the sub-chiefery level. The Belgian administration imposes ethnic membership criteria under which owners of 10 or more head of cattle are classified as Tutsi and the remainder of the population divided by profession among the Hutu and Twa. Identity cards are issued marking each man as a member of his assigned ethnic group. |
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| 1937 | | The first airplane flown directly from Belgium to Ruanda-Urundi lands at Usumbura. |
| | The Catholic Church in the Vicarate of Urundi claims 253,665 baptized members and 230,000 catechumens. |
| 1939 | | The Port of Usumbura on Lake Tanganyika is opened after two years of construction. The Upper Congo & Great Lakes Railway connects Usumbura with Albertville, Belgian Congo for traffic heading to the Atlantic ports of Matadi and Lobito as well as Kigoma, Tanganyika for movement of goods to the Indian Ocean port of Dar es Salam. |
| 1943 | October 17 | King Mutara III Rudahigwa of Ruanda, his chiefs and sub-chiefs are baptized in an effort attract the support of the Catholic Church and colonial authorities. |
| During the Year | The Belgian authorities replace Ruanda's Hutu chiefs with Tutsis appointed by the king. |
| 1944 | December 25 | King Yuhi V Musinga of Ruanda dies after 13 years of exile in the Belgian Congo. |
| 1945 | | King Mutara III Rudahigwa of Ruanda proposes an end to the Ubuhake, a feudal tax requiring Hutu tenant farmers to hand over half of their crops to the king. |
| 1946 | December 13 | The United Nations General Assembly grants Belgium a trusteeship over Ruanda-Urundi to, "promote the political, economic and social progress of the population along with development their education as well as promoting their progressive evolution to the capacity of self rule." |
| 1949 | | King Mutara III Rudahigwa of Ruanda opposes the chicote, public beating of adult men before their families as punishment for a variety of offenses. The colonial administration expresses its dissatisfaction. |
| 1951 | | Belgium launches a ten year development program to promote agricultural production (coffee, cotton, food crops) and cattle grazing. |
| 1952 | July 14 | Belgium expands the functions of the native administration under pressure from the United Nations Trusteeship Council. |
| 1954 | July 14 | Belgium reorganizes the legislative councils with a view to democratizing native institutions at all levels establishing: |
| | Sub-Chiefery Councils comprised of a Sub-Chief and one member for every 500 subjects |
| | Chiefery Councils comprised of a Chief and 5 to 9 Sub-Chiefs elected by their peers and an equal number of notables |
| | Territorial Councils comprised of all Chiefs and an equal number of Sub-Chiefs elected by their peersand a number of notables equal to the total number of chiefs and sub-chiefs |
| | A High Council of the Country replacing the King's Councils which consisted solely of princes chosen by family and region. The King supported by a vice president appointed by the vice governor general presides over the High Council which is composed of the presidents of the territorial councils, 6 chiefs chosen by their peers, a representative of each territorial council, 4 members chosen for their understanding of socio-economic, religious and cultural issues and 4 native holder of Civic Merit Awards. |
| During the Year | The Socialist come to power in Brussels and promote the establishment of public secondary schools teaching the same curriculum as their counterparts in Belgium. Le College Interracial d'Usumbura and the Athnee de Usumbura offer instruction in the humanities and Greco-Roman classics. |
| | The Ubuhake, a contract imposed on Hutu tenant farmers in Ruanda requiring payment of half their crop to the king, is surpressed. |
| | The colonial administration ends the Uburetwa, a practice requiring most Hutus to work without pay for two days a week on public works directed by a Tutsi chief. |
| | The Ruvyironza Experimental Farm is established at Mahwa to improve cattle production in the territory. The farm introduces the Sahiwal breed from Pakistan for meat and the Jersey for milk. |
| 1956 | | King Mutara III Rudahigwa under pressure from his advisors and acting through the High Council demands a precise timetable for the accession of Ruanda to independence. |
| | Prince Louis Rwagasore, son of Urundi's King Mwambutsa, requests a constitution for the country based on that of Belgium. |
| | Sub-Chiefery Councils are chosen by secret ballot and universal suffage on the insistance of Governor Jean Paul Harroy who is no longer willing to leave the composition of councils to the discretion of the sub-chief. |
| 1957 | May | The Parmehutu, Hutu Emancipation Movement, led by Grégoire Kayibanda issues the Bahutu Manifesto calling for the political, social and economic emancipation of Ruanda’s Hutu majority. The Catholic Church makes common cause with the Hutu’s and the Belgian administration takes laisse faire approach that eventually leads to a Hutu revolt. |
| | A pre-university center is established at Astrida. |
| 1958 | | King Mutara III Rudahigwa of Ruanda opposes the chicote, public beating of adult men before their families as punishment for a variety of offenses. The colonial administration expresses its dissatisfaction. |
| | Prince Louis Rwagasore urges the creation of political parties. Twenty three parties are formed in Urundi over the next two years. |
| 1959 | February 15 | Ruandan Joseph Gitera founds the Association for the Social Promotion of the Masses. |
| April - May | The Belgian Government creates a committee to study political problems in Ruanda-Urundi. |
| July 25 | King Mutara III Rudahigwa of Ruanda dies in Usumbura under mysterious circumstances and without a successor. |
| July 28 | Kigeri V Ndahindurwa, half brother of King Mutara III Rudahigwa, is placed on the Ruandan throne by the late sovereign’s councilors. Kigeri’s accession, considered illegitimate by the Hutu, brings a continuation of policies designed to defend the aristocratic privileges of the Tutsi. |
| September 3 | Francois Rukeba founds the Union Nationale Rwandaise which supports the Tutsi monarchy. |
| September 14 | The Ruandan Democratic Rally is organized by Belgian Resident André Preud'homme and his adjudant M. Regnier. The members are graduates of the Groupe Scolaire d’Astrida. |
| October 11 | Monsignor Ntuyahaga is appointed as the first native Catholic Bishop of Usumbura. |
| October 18 | The Parmehutu is organized as a political party, the Party of the Hutu Emancipation Movement, by Father Andriatis and Canon Ernotte. |
| November 1 | Dominique Mbonyumutwa, Sub-Chief of Ndiza, is assassinated by members of the Union Nationale Rwandaise supporters of Ruanda's Tutsi monarchy plunges the country into bloody ethnic warfare in which members of the Tutsi minority are massacred. Hutus hold only 10 of Ruanda's 520 sub-chieftaincies at the time. |
| December 3 | The Urundi People's Party is formed to promote political, social and cultural emancipation of the lower classes in a federation with Ruanda. Colonist Albert Maus, a leader in the Hutu emancipation movement, is among the party's chief backers. The People's Party is more or less equivalent to the Parmehutu in Ruanda. |
| December 25 | The Belgian Government, acting on recommendations of the Ruanda-Urundi Study Committee, issues a decree reorganizing the political structure with a view to democratizing native institutions. The administrative link with the Belgian Congo is severed, provisional communal councils are established, the chiefdoms are maintained but the chiefery councils are replaced with temporary councils, legislative councils are established for both countries and a General Council is established to decide issues affecting both countries. |
| During the Year | A meeting of the United Nations Trusteeship Council is convened in Usumbura. Ruanda’s Hutu majority, fearing independence bring a return to pre-colonial regime under which the Tutsi held absolute power held, demands social reform before the independence. |
| | A two year expansion project begins at the Port of Usumbura. |
| 1960 | January 7 | Prince Louis Rwagasore of Urundi founds Unity for National Progress (UPRONA) to promote a platform calling for immediate independence and social justice. |
| February | Joseph Birori, a Mutare prince and son of Pierre Baranyanka, founds the Urundi Christian Democratic Party. The PDC calls for independence, creation of a democratic state based on Christian principles of justice and equality and maintaining close ties with Belgium. The party is accused of neo-colonialist tendencies by certain segments of public opinion. |
| March 31 | The United Nations proclaims an amnesty for crimes committed during the Hutu uprising in Ruanda which began on November 1, 1959. The Belgian administration lists 74 official deaths of which 61 were Hutus assassinated by the Tutsi militia attempting to supress the revolution. Some 150,000 Tutsis, especially chiefs and sub-chiefs, left the country. |
| July 25 | King Kigeri V Ndahindurwa is forced to leave Ruanda along with 200,000 Tutsi. |
| August 23 -31 | Representatives of the Belgian Government, colonial administrators, the temporary commission on Ruanda-Urundi and the political parties convene in Brussels to discuss problems in Urundi and the need for modification of the temporary decree issued the previous December 25th with regards to communal elections; organization and installation of new administrative structures and the future of Usumbura, the common capital of both Urundi and Ruanda. |
| September 20 | A Common Front is formed by a dozen political parties opposed to UPRONA which wants immediate independence for Urundi. The colonial administration supports the Front and seeks to undermine the popularity of UPRONA leader Prince Louis Rwagasore who it imprisons for most of the electoral campaign. |
| October 18 | Ruanda is granted internal autonomy. |
| October 19 | Grégoire Kayibanda is appointed Prime Minister of Ruanda. |
| October 26 | Prime Minister Grégoire Kayibanda forms the first provisional government of Ruanda. |
| December 8 -15 | Local council elections are held in Urundi. The Common Front emerges victorious owing to fraud and voter intimidation on the part of the colonial administration. The Front wins 1648 seats with 45% of the vote. UPRONA wins 545 seats with slightly less than 19% of the vote. |
| December 20 | The United Nations General Assembly approves Resolution 1579 ordering Belgium to delay legislative elections in Ruanda-Urundi scheduled for January 28, 1961 and introduction of universal suffrage at such time as these elections are held. Belgium reacts with legislative ordinances establishing a temporary council in Urundi elected by the communal councilors. The Common Front wins 80% of the seats in the temporary council. |
| During the Year | The University Center of Usumbura is established with faculties of philosophy & letters and political, economic and social sciences. The School of Agronomy is transferred from Astrida to Usumbura. |
| | Usumbura airport is built at Gakumbu. Sabena and Sobelair DC-4s and DC-6s provide direct service between Ruanda-Urundi and Belgium. |
| 1961 | January 28 | President Dominique Mbonyumutwa proclaims the Republic of Rwanda. |
| September 18 | The Parmehutu wins 78% of the vote cast in elections for the Rwandan National Assembly. |
| | Urundi's legislative elections are held under United Nations supervision. UPRONA wins 58 of 64 seats in the assembly. Urundi becomes Burundi, a constitutional monarchy under King Mwambutsa IV Bangilicenge. |
| September 25 | Legislative elections and a referendum on the Ruandan monarchy are conducted under United Nations auspices. The republic is upheld by 80% of the electorate. |
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| September 28 | Prince Louis Rwagasore becomes Prime Minister of Burundi. |
| October 13 | Prince Louis Rwagasore is assassinated at a restaurant bar in Tanganyika. |
| October 26 | Parmehutu leader, Grégoire Kayibanda, secretary to the Archbishop of Rwanda is elected President of the Rwandan Republic. |
| December 21 | Burundi is granted internal autonomy. Belgium retains control of the country's foreign relations, defense, police and finances. |
| 1962 | April 2 | The High Court of Burundi attributes the assassination of Prince Louis Rwagasore to a Greek gunman named Kageorgis hired by the principal leaders of the Christian Democratic Party Joseph Birori and Jean Ntidendereza. The defendants are sentenced to death by hanging at Gitega. |
| June 28 | The United Nations General Assembly resolves to remove the Belgian trusteeship over Rwanda and Burundi, fixes July 1st as the date of their accession to independence and demand evacuation of Belgian troops by August 1st. The resolution is approved unanimously with 10 abstentions from the Communist block. |
| July 1 | Belgium declares Rwanda and Burundi independent at the insistence of the United Nations Trusteeship Council. |
