Complex sentence: Combined, "Wu" plus "di" creates the name "Wudi", the emperor's Posthumous name used for historical and for religious purposes, such as offering him posthumous honors at his tomb.
Split into simpler sentences: Combined, "Wu" plus "di" creates the name "Wudi". Wudi being this emperor's Posthumous name, used for historical and for religious purposes, such as offering him posthumous honors at his tomb.