 Agricultural items, such as oranges, lemons, pistachio and sugar cane, were brought to Sicily, the native Christians were allowed nominal freedom of religion with jaziya (tax on non-Muslims, imposed by Muslim rulers) to their rulers for the right to practise their own religion privately.However, the Emirate of Sicily began to fragment as inner-dynasty related quarrels took place between the Muslim regime.By the 11th century, mainland southern Italian powers were hiring ferocious Norman mercenaries, who were Christian descendants of the Vikings; it was the Normans under Roger I who conquered Sicily from the Muslims.