Short answers, pulled from the story.
The Republic of the Congo gained its freedom on the 30th of June 1960. This event followed pressure from nationalist movements led by Patrice Lumumba that forced Belgium to grant independence.
Katangan forces executed Patrice Lumumba on the 17th of January 1961 at a pig farm near Élisabethville. Belgian government support helped Katangan forces retain mining rights for copper and diamonds during this period.
The United Nations peacekeeping mission operated in the country from 1960 to 1964 with up to 20,000 troops deployed as part of ONUC. This operation became the largest, most complex, and most costly ever carried out by the UN before all military components were withdrawn by the 30th of June 1964.
Joseph-Désiré Mobutu maintained power from his 1965 coup until he was overthrown in 1997. He declared himself president for five years initially but established authoritarian rule that lasted until 1997 through the Popular Movement of the Revolution party.
Joseph Désiré Mobutu changed the country's name to Republic of Zaïre in 1971. This renaming followed his seizure of absolute power in 1965 and reflected a desire to erase colonial legacy and assert African identity.