Complex sentence: Trinquier was a member of the Cité catholique fundamentalist group which gathered many former members of the OAS pro- "French Algeria" terrorist group and opened a subsidiary in Argentina near the end of the 1950s.
Split into simpler sentences: Trinquier was a member of the Cité catholique fundamentalist group. It recruited many former members of the OAS pro- "French Algeria" terrorist group and opened a subsidiary in Argentina near the end of the 1950s.