Short answers, pulled from the story.
The State of Katanga was a breakaway republic that declared independence from Congo-Léopoldville on the 11th of July 1960 under CONAKAT leader Moïse Tshombe. It was dissolved in 1963 following a United Nations invasion and reintegrated into Congo as Katanga Province.
Moïse Tshombe, leader of the CONAKAT political party, led Katanga's secession and served as the state's president. He was backed by the mining company Union Minière du Haut-Katanga and by Belgian military advisers.
CONAKAT and Belgian settlers in Katanga wanted to protect their political and economic position after Congo's independence in June 1960, particularly control over the region's copper wealth. Union Minière du Haut-Katanga had begun funding CONAKAT and paying Tshombe in March 1960, ahead of the declaration.
United Nations forces ended the secession through Operation Grandslam, launched on the 28th of December 1962, which brought Élisabethville under UN control within three days. Tshombe conceded defeat on the 15th of January 1963 and allowed UN forces into his last stronghold, Kolwezi, on the 21st of January.
Patrice Lumumba, the Congolese prime minister who opposed Katanga's secession, was sent to Élisabethville on the 17th of January 1961 after being ousted in a coup by Mobutu Sese Seko. He was tortured and executed inside Katanga shortly after his arrival.
Katanga's Gendarmerie relied on Belgian officers along with mercenaries recruited from Britain, Southern Rhodesia, France, and South Africa. Notable French recruits included Roger Faulques, Roger Trinquier, and Edgard Tupët-Thomé, many of them veterans of the Algerian War.