The city was founded in 734 BC by the Phoenicians as Ziz ('flower'). Palermo then became a possession of Carthage, before becoming part of the Roman Republic, the Roman Empire and eventually part of the Byzantine Empire, for over a thousand years. The Greeks named the city Panormus meaning 'complete port'. From 831 to 1072 the city was under Arab rule during the Emirate of Sicily when the city first became a capital. The Arabs shifted the Greek name into Balarm, the root for Palermo's present-day name. Following the Norman reconquest, Palermo became the capital of a new kingdom (from 1130 to 1816), the Kingdom of Sicily and the capital of the Holy Roman Empire under Frederick II Holy Roman Emperor and Conrad IV of Germany, King of the Romans. Eventually Sicily would be united with the Kingdom of Naples to form the Kingdom of the Two Sicilies until the Italian unification of 1860.

Answer this question, if possible (if impossible, reply "unanswerable"): Who changed the name of Palermo to Ziz?
unanswerable