Gavrilo was born around 1605–1610 in the region of Stari Vlah (present-day Serbia) into the noble Rajić family.
[1] In 1653, he decided to travel to Russia to ask for material support for the Serbian Patriarchate of Peć.
After meeting with Metropolitan Arsenije of Herzegovina on Christmas Eve, he went first to Wallachia and arrived in Trgovište where he tried to reconcile the Wallachian Prince Matei Basarab with the Cossack Hetman Bohdan Khmelnytsky.
From there, Gavrilo traveled to Russia in 1654, taking with him two books for printing: Lives of Serbian Emperors and Patriarchs and Typikon against Latin Heresy of Saint Nil Kabasilas.
[2] Soon after, he changed his mind and left Russia arriving back in the Ottoman Empire in 1659.