 In 1448 he defeated the Christian coalition at the Second Battle of Kosovo (the first one took place in 1389).When the Balkan front was secured, Murad II turned east to defeat Timur's son, Shah Rokh, and the emirates of Karamanid and Çorum-Amasya.In 1450 Murad II led his army into Albania and unsuccessfully besieged the Castle of Kruje in an effort to defeat the resistance led by Skanderbeg.