Complex sentence: In the early Middle Ages the city had a troubled life due to its location near the main road of communication, until, in the 956, it freed from the Papal authority and organized istelf as commune with laws of its own.
Split into simpler sentences: In the early Middle Ages the city had a troubled life due to its location near the main road of communication. But in 956 it was freed from the Papal authority and organized itself as a commune with laws of its own.