Complex sentence: The first unit, company A, was recruited and organized by Capt. R. A. Stewart in June 1861 whose members were mostly from Pointe Coupee Parish, Louisiana and surrounding parishes.
Split into simpler sentences: The first unit, company A, was recruited and organized by Capt. R. A. Stewart in June 1861. The unit's members were mostly from Pointe Coupee Parish, Louisiana and surrounding parishes.