Complex sentence: The revolt had begun in the spring of 1944, initiated by the Czechoslovak Agrarian party, part of the Social Democratic party, the Communist party, sectors of the Slovak nationalists, and army officers.
Split into simpler sentences: The revolt had begun in the spring of 1944. It was initiated by the Czechoslovak Agrarian party, part of the Social Democratic party, the Communist party, sectors of the Slovak nationalists, and army officers.