Complex sentence: Antony reinvaded Armenia in 34 BC, captured Artavasdes, and took him to Alexandria, in 31 BC he was beheaded by Cleopatra VII of Egypt without revealing the whereabouts of the royal treasury.
Split into simpler sentences: Antony reinvaded Armenia in 34 BC, captured Artavasdes, and took him to Alexandria. In 31 BC he was executed by beheading on the behalf of Cleopatra VII of Egypt, having not revealing the whereabouts of the royal treasury.