Complex sentence: Unusually for 1914--15 the 5th Light Infantry was an entirely Muslim unit, mainly comprising Ranghars (Muslims of Rajput origin) and Pathans, commanded by British and Indian officers.
Split into simpler sentences: Unusually for 1914--15 it was an entirely Muslim unit. The 5th Light Infantry mainly comprised Ranghars (Muslims of Rajput origin) and Pathans, commanded by British and Indian officers.