Complex sentence: Hay's inspiration for his schoolmaster gimmick came from his sister who was a full-time teacher, he first gained fame for his trademark character in 1910, following a performance when he was offered a contract to perform at a theatre in Belper.
Split into simpler sentences: Hay's inspiration for his schoolmaster came from his sister who was a full-time teacher. He first gained fame for his trademark character in 1910, following a performance when he was offered a contract to perform at a theatre in Belper.