Güyük invaded Transylvania in three columns through the Tihuţa and Oituz Passes and the Timiş-Cerna Gap, while Subutai attacked through the fortified Verecke Pass towards central Hungary. Güyük sacked Sibiu, Cisnadie, Alba Iulia, Bistriţa, Cluj-Napoca, Oradea as well as the Hungarian king's silver mine at Rodna. This prevented the Transylvanian nobility from aiding King Béla IV in the crucial Battle of Mohi. A separate Mongol force destroyed the Cumans near the Siret River and annihilated the Cuman Catholic Bishopric of Milcov.