Complex sentence: Clement VII escaped to safety through this passage during the Sack of Rome in 1527, when troops of the Holy Roman Emperor, Charles V, massacred almost the entire Swiss Guard on the steps of St Peter's Basilica.
Split into simpler sentences: Clement VII escaped to safety through this passage during the Sack of Rome in 1527. Troops of the Holy Roman Emperor, Charles V, massacred almost the entire Swiss Guard on the steps of St Peter's Basilica.