Zavala Monastery, located about 40 km southwest of Trebinje, on the south-west side of Popovo Polje /Popovo Field/, below the Ostrog Hill, which in Russian, Old-slavonic and Serbian language means stronghold or fortified place. The area of Popovo polje is located in the south of Herzegovina, and bears the earliest name of Popovo. The earliest written document which specifies the Popovo as the significant place is the letter of the Popovo Municipality to the Dubrovnik Municipality, 1169-1170. The tradition of the antiquity of this shrine has it that the original church was build by Emperor Constantine and his mother Helen. The population of the whole Primorje in the 14th and the 15th century was Serbia and of Orthodox confession, and the Serbian prince Miroslav, brother of Stefan Nemanja had his court in Ston on Peljesac peninsula. In Zavala, on the localities around the Medieval ruined churches and monuments of the Hum Diocese, there are remains of 45 Medieval churches, as well as at the very entrance to the nearby Vjetrenica Pecina Cave, making the entire spiritual complex. One of the Medieval monuments of Herzegovina was the medieval fortification of Popovski grad, in the hills above the Zavala Monastery, which is known in historical records as the seat of Herceg Stefan Vukčić Kosača – the Herzog of Sveti Sava. The Zavala Monastery is dedicated to Entrance of the Holy Virgin to the temple. According to the national oral tradition it is endowment of Serbian Kind Dragutin. The year of 1271, inscribed in the old seal of the Zavala monastery is often mentioned in regard with the foundation of the Zavala Monastery. Along with Žitomislić and Tvrdoš monasteries, Zavala Monastery is one of the most important centers of cultural life in East Herzegovina. Stojan Jovanovic in Zavala Monastery made his vow to religious life and became the Saint Vasilije Ostroski – the Saint Basil of Ostrog. He was born on 28 December 1610 in the nearby village of Mrkonjici, by the father Petar and mother Ana Jovanovic.
The uniqueness of Zavala Monastery architecture is determined with its solitude secluded location what makes it true monastic sanctuary. The tiny church has one-have base with semicircle apse on the eastern side from the outside. The norther side of the church and altar are carved into the large cliff. The famous fresco painter Georgije Mitrofanović who fresco-painted Chilandary Monastery on Athos Mountain stayed here during the 17th century before he had arrived here. He also had decorated Monastery of Dobrićevo near Bileca in Herzegovina.
The earliest document on Zavala Monastery date from 1514 which testified that its Abbot had bought large vineyards. Many significant church manuscripts were written during this period. Along the course of the next century monastic library was enriched with new books from Sremski Karlovci and Belgrade, among which were numerous Russian books on lives of saints and gospels. Saint Vasilije Ostroski started his monastic life in Zavala Monastery.
During the Second World War Zavala Monastery experienced serious damage when Ustashas destroyed and plundered its valuable collections. In the most recent wars, after the break up of Yugoslavia, Zavala Monastery was damaged and abandoned, when the village of Zavala was completely destroyed. Zavala Monastery was restored after the war and regained its monastic life. Zavala Monastery together with Tvrdos and Zitomislic Monasteries represent the core of the culture and the Orthodox religion of Herzegovina.