Rwanda and neighbouring Burundi were assigned to Germany by the Berlin Conference of 1884, and Germany established a presence in the country in 1897 with the formation of an alliance with the king.
In 1957, a group of Hutu scholars wrote the "Bahutu Manifesto". This was the first document to label the Tutsi and Hutu as separate races, and called for the transfer of power from Tutsi to Hutu based on what it termed "statistical law".
Hutu activists responded by killing Tutsi, both the elite and ordinary civilians, marking the beginning of the Rwandan Revolution.
On 1 November 1959 Dominique Mbonyumutwa, a Hutu sub-chief, was attacked close to his home in Byimana, Gitarama prefecture, by supporters of the pro-Tutsi party. Mbonyumutwa survived, but rumours began spreading that he had been killed.
In 1990, the army began arming civilians with weapons such as machetes, and it began training the Hutu youth in combat, officially as a programme of "civil defense" against the RPF (Rwandan Patriotic Front) threat, but these weapons were later used to carry out the genocide.
In the early years of Habyarimana's regime, there was greater economic prosperity and reduced violence against Tutsi. Many hardline anti-Tutsi figures remained, however, including the family of the first lady Agathe Habyarimana, who were known as the akazu or clan de Madame, and the president relied on them to maintain his regime. When the RPF invaded in 1990, Habyarimana and the hardliners exploited the fear of the population to advance an anti-Tutsi agenda which became known as Hutu Power.
Rwanda also purchased large numbers of grenades and munitions from late 1990; in one deal, future UN Secretary-General Boutros Boutros-Ghali, in his role as Egyptian foreign minister, facilitated a large sale of arms from Egypt.
In the 1980s, a group of 500 Rwandan refugees in Uganda, led by Fred Rwigyema, fought with the rebel National Resistance Army (NRA) in the Ugandan Bush War, which saw Yoweri Museveni overthrow Milton Obote. These soldiers remained in the Ugandan army following Museveni's inauguration as Ugandan president, but simultaneously began planning an invasion of Rwanda through a covert network within the army's ranks. In October 1990, Rwigyema led a force of over 4,000 rebels from Uganda, advancing 60 km (37 mi) into Rwanda under the banner of the Rwandan Patriotic Front (RPF).
Rwigyema was killed on the third day of the attack, and France and Zaire deployed forces in support of the Rwandan army, allowing them to repel the invasion.
Rwigyema's deputy, Paul Kagame, took command of the RPF forces, organizing a tactical retreat through Uganda to the Virunga Mountains, a rugged area of northern Rwanda. From there, he rearmed and reorganised the army, and carried out fundraising and recruitment from the Tutsi diaspora.
Kagame restarted the war in January 1991, with a surprise attack on the northern town of Ruhengeri.
In 1992, the hardliners created the Coalition for the Defense of the Republic (CDR) party, which was linked to the ruling party but more right wing, and promoted an agenda critical of the president's alleged "softness" with the RPF.
In June 1992, following the formation of a multiparty coalition government in Kigali, the RPF announced a ceasefire and began negotiations with the Rwandan government in Arusha, Tanzania.
In early 1993, several extremist Hutu groups formed and began campaigns of large scale violence against the Tutsi.
In March 1993, Hutu Power began compiling lists of "traitors" whom they planned to kill, and it is possible that Habyarimana's name was on these lists; the CDR (the Coalition for the Defence of the Republic) were publicly accusing the president of treason.
In October 1993, the President of Burundi, Melchior Ndadaye, who had been elected in June as the country's first ever Hutu president, was assassinated by extremist Tutsi army officers.
On 11 January 1994, General Roméo Dallaire, commander of UNAMIR (United Nations Assistance Mission for Rwanda), sent his "Genocide Fax" to UN Headquarters. The fax stated that Dallaire was in contact with "a top level trainer in the cadre of Interhamwe-armed militia of MRND." The informant—now known to be Mathieu Ngirumpatse's chauffeur, Kassim Turatsinze, a.k.a. "Jean-Pierre" – claimed to have been ordered to register all Tutsi in Kigali. According to the memo, Turatsinze suspected that a genocide against the Tutsis was being planned, and he said that "in 20 minutes his personnel could kill up to 1000 Tutsis". Dallaire's request to protect the informant and his family and to raid the weapons caches he revealed was denied.
Following Habyarimana's death, on the evening of 6 April, a crisis committee was formed; it consisted of Major General Augustin Ndindiliyimana, Colonel Théoneste Bagosora, and a number of other senior army staff officers. The committee was headed by Bagosora, despite the presence of the more senior Ndindiliyimana. Prime Minister Agathe Uwilingiyimana was legally next in the line of political succession, but the committee refused to recognise her authority. Roméo Dallaire met with the committee that night and insisted that Uwilingiyimana be placed in charge, but Bagosora refused, saying Uwilingiyimana did not "enjoy the confidence of the Rwandan people" and was "incapable of governing the nation". The committee also justified its existence as being essential to avoid uncertainty following the president's death. Bagosora sought to convince UNAMIR and the RPF that the committee was acting to contain the Presidential Guard, which he described as "out of control", and that it would abide by the Arusha agreement.
The genocide was organised by members of the core Hutu political elite, many of whom occupied positions at top levels of the national government. Most historians agree that a genocide against the Tutsi had been planned for at least a year. However the assassination of Rwandan president Juvénal Habyarimana on 6 April 1994 created a power vacuum and ended peace accords. Genocidal killings began the following day when soldiers, police, and militia executed key Tutsi and moderate Hutu military and political leaders.
The ICTR (International Criminal Tribunal for Rwanda) prosecution was unable to prove that a conspiracy to commit genocide existed prior to 7 April 1994.
On 7 April, as the genocide started, RPF (the Rwandan Patriotic Front) commander Paul Kagame warned the crisis committee and UNAMIR that he would resume the civil war if the killing did not stop.
On 9 April, UN observers witnessed the massacre of children at a Polish church in Gikondo.
Thousands sought refuge in the Official Technical School (École Technique Officielle) in Kigali where Belgian UNAMIR soldiers were stationed. On 11 April, the Belgian soldiers withdrew, and Rwandan armed forces and militia killed all the Tutsi.
On 12 April, the Belgian government, which was one of the largest troop contributors to UNAMIR, and had lost ten soldiers protecting Prime Minister Uwilingiliyimana, announced that it was withdrawing, reducing the force's effectiveness even further.
One such massacre occurred at Nyarubuye. On 12 April, more than 1,500 Tutsis sought refuge in a Catholic church in Nyange, then in Kivumu commune.
The first rumors of RPF killings emerged after 250,000 mostly Hutu refugees streamed into Tanzania at the border crossing of Rusumo on 28 April 1994.
After the RPF took control of the border crossing at Rusumo on 30 April, refugees continued to cross the Kagera River, ending up in remote areas of Tanzania.
During the remainder of April and early May, the Presidential Guard, gendarmerie and the youth militia, aided by local populations, continued killing at a very high rate. Gerard Prunier estimates that during the first six weeks, up to 800,000 Rwandans may have been murdered, representing a rate five times higher than during the Holocaust of Nazi Germany. The goal was to kill every Tutsi living in Rwanda and, with the exception of the advancing RPF army, there was no opposition force to prevent or slow the killings.
By 16 May, RPF (the Rwandan Patriotic Front) had cut the road between Kigali and Gitarama, the temporary home of the interim government.
The United Nations High Commissioner for Refugees (UNHCR) began hearing concrete accounts of atrocities and made this information public on 17 May.
On 17 May 1994, the UN passed Resolution 918, which imposed an arms embargo and reinforced UNAMIR, which would be known as UNAMIR II. The new soldiers did not start arriving until June, and following the end of the genocide in July, the role of UNAMIR II was largely confined to maintaining security and stability, until its termination in 1996.
By 13 June, RPF (the Rwandan Patriotic Front) had taken Gitarama itself, following an unsuccessful attempt by the Rwandan government forces to reopen the road; the interim government was forced to relocate to Gisenyi in the far north west.
On 23 June, around 2,500 soldiers entered southwestern Rwanda as part of the French-led United Nations Opération Turquoise.
At the end of July 1994, Kagame's forces held the whole of Rwanda except for the zone in the south-west which had been occupied by a French-led United Nations force as part of Opération Turquoise.
The Liberation Day for Rwanda would come to be marked as 4 July and is commemorated as a public holiday.
The ICTR (International Criminal Tribunal for Rwanda) officially closed on 31 December 2015, and its remaining functions were handed over to the Mechanism for International Criminal Tribunals.
On 20 March 2017, Pope Francis acknowledged that while some Catholic nuns and priests in the country were killed during the genocide, others were complicit in it and took part in preparing and executing the genocide.