Complex sentence: His father was a senior officer (tribune) in the Imperial Horse Guard, a unit of the Roman army, and was later stationed at Ticinum (now Pavia), in northern Italy, where Martin grew up.
Split into simpler sentences: His father was a senior officer (tribune) in the Imperial Horse Guard, a unit of the Roman army. He was later stationed at Ticinum (now Pavia), in northern Italy, where Martin grew up.