Complex sentence: The mausoleum is so named for Mausolus of Caria (377-353/2 BC), a ruler in what is now Turkey who was a profound patron of Hellenistic culture.
Split into simpler sentences: The mausoleum is so named for Mausolus of Caria (377-353/2 BC), a ruler in what is now Turkey. He was a profound patron of Hellenistic culture.