 After Rákóczi did not obey the Grand Vizier's summons, Köprülü's Ottoman and Tatar troops invaded Transylvania, destroying Gyulafehérvár (Alba Iulia) and other towns and capturing tens of thousands of prisoners in September.Köprülü withdrew his troops from the principality only after the head of the Prince's Council, Ákos Barcsay was elected prince by the Diet on 7 October.A civil war broke out, with Rákóczi seeking Leopold I's support and Barcsay urging the Ottomans to intervene.