Mouvement National Congolais (MNC), led by Patrice Lumumba. The Belgian colonial administration attempted to put in motion a plan for decolonization but wanted more time to build up a Congolese administration and prepare for their exit, so they attempted to isolate the country from Africa and Europe and suppress political organization. This became increasingly difficult as Congolese nationalism became more popular, so in July 1958 the Belgian government established a study group to consider new reforms in the colony. In response to the study group's findings, the colonial administration decided it would announce constitutional changes in the Congo on 13 January 1959. On 28 December 1958, Lumumba organized a major MNC rally in Léopoldville where he reported on his attendance of the All-African Peoples' Conference in Accra, Ghana earlier that month. Noting the success of the rally, Kasa-Vubu decided to organize his own event one week later, on Sunday January 4, 1959 to discuss African nationalism. ABAKO requested permission to hold the meeting at Léopoldville's YMCA (Young Men's Christian Association) building, but the municipal government, having been given short notice, communicated that only a "private meeting" would be authorised. Belgian officials also warned that if the event became political, ABAKO leaders would be held responsible. Riots Interpreting the administration's warnings as a prohibition of the meeting, ABAKO leadership attempted on 3 January to postpone their event, but on Sunday, 4 January, a large crowd gathered at the YMCA anyway. Kasa-Vubu and other ABAKO officials arrived to send the protesters home. They were unable to calm the crowd, and the violence began following the protesters' refusal to disperse. The crowd began throwing rocks at police and attacking white motorists. The initial group of protesters were soon joined by 20,000 Congolese leaving a nearby soccer stadium. At the time press accounts estimated that 35,000 Africans were involved in the violence, which quickly spread as the rioters attempted to enter the European section of the capital. Rioters allegedly smashed and looted storefronts, burned Catholic missions and beat Catholic priests. Many demonstrators chanted "indépendance immédiate". Order was restored with the use of African police officers in the employ of the colonial government and with armored cars under the direction of General Émile Janssens. Colonial authorities arrested as many as 300 Congolese, including Kasa-Vubu, who would later become the newly independent Congo's first president, Simon Mzeza and ABAKO vice-president Daniel Kanza and charged them with