Sicily fell under the control of the Holy Roman Empire in 1194. Palermo was the preferred city of the Emperor Frederick II. Muslims of Palermo emigrated or were expelled during Holy Roman rule. After an interval of Angevin rule (1266–1282), Sicily came under control of the Aragon and Barcelona dynasties. By 1330, Palermo's population had declined to 51,000. From 1479 until 1713 Palermo was ruled by the Kingdom of Spain, and again between 1717 and 1718. Palermo was also under Savoy control between 1713 and 1717 and 1718–1720 as a result of the Treaty of Utrecht. It was also ruled by Austria between 1720 and 1734.
During what years did Austria rule Palermo? (If the question is unanswerable, say "unanswerable")
1720 and 1734