Complex sentence: He served in the English New Model Army in Scotland and was with General George Monck, and accompanied Monck when he marched into England in 1660 at the head of his army and restored King Charles II to the throne.
Split into simpler sentences: He served in the English New Model Army in Scotland under General George Monck. He accompanied Monck when he marched into England in 1660 at the head of his army and restored King Charles II to the throne.