He was born in the beginning of the 14th century as the grandson of Dmitar Nemanjić, a descendant of Vukan Nemanjić. He was a noble and age-mate of Serb Emperor Stefan Dušan. In 1342, Vratko and Oliver, as allies of John VI Kantakouzenos in the Byzantine civil war of 1341–1347, led the Serbian army to attack Serres. The attack failed disastrously, as dysentery (caused by the excessive consumption of must) befell the attackers, and 1,500 men died of it.