Complex sentence: A rival government, the Free Republic of the Congo, founded by Antoine Gizenga and Lumumba supporters in the eastern city of Stanleyville, gained Soviet support but was crushed in early 1962.
Split into simpler sentences: A rival government, the Free Republic of the Congo, was founded in the eastern city of Stanleyville by Lumumba supporters led by Antoine Gizenga. It gained Soviet support but was crushed in early 1962.