In 1627, on the high bank of the Lesnoy Voronezh River, by the order of Tsar Mikhail Feodorovich Romanov, Elder Joseph founded the male Trinity Monastery. The monastery was located in an oak grove by the river, the opposite bank of which was called the "Nogai side." Elder Joseph was assisted by Elders Pafnutiy, Agafonik, and Nifont. The monastery was allocated forest and hay lands, and by 1635 it owned seven peasant households. In 1636, the monks received the blessing of Archbishop Antoniy of Ryazan to build a church in the name of the Holy Trinity with an altar dedicated to the Assumption of the Most Holy Theotokos. The first church was wooden and small. On September 5 of the same year, Tsar Mikhail Feodorovich instructed the yaselnichy and voivodes Ivan Birkin and Mikhail Speshnev to go to the Wild Field and build a new city, Kozlov, as part of the Belgorod defensive line, since the Tula line was no longer holding back the attacks of the Crimean and Nogai Tatars.

By the mid-17th century, the Belgorod defensive line was completed. The monastery, located south of Kozlov, often suffered from Tatar and Kalmyk raids. In 1643, the Kozlov voivode Prince Ivan Rostovsky informed Tsar Mikhail Feodorovich about Tatar attacks that the Cossacks did not allow into the city. For their heroic defense, the tsar rewarded the defenders with gold and resources for their arrangements. Don and Yaik Cossacks, as well as soldiers and other serving people, were invited for permanent residence here. In the spring and summer of 1644, 30 Tatar murzas besieged the city. In a letter to Khan Mehmed Girey, Tsar Mikhail Feodorovich noted that almost all of Crimea had been in these places. Kozlov was on the Diplomatic Road from Moscow to Bakhchisarai, along which captives were returned, for whose release a special tax was introduced.

After the October Revolution, the looting of churches and monasteries began. On January 19, 1918, Patriarch Tikhon mentioned these events in his message, and the next day, a decree was adopted on the separation of schools from the Church. On February 2 of the same year, a decree on freedom of conscience and religious societies was issued. The Kozlovsky Monastery also suffered: its property was requisitioned, and the monks were evicted. Since the beginning of 1999, services resumed in the church, with Archpriest Georgy Politayev becoming the rector. On April 5, 1999, the church building was transferred to the Tambov Diocesan Administration. A miracle occurred at the parish Assumption Church: a fragrance emanated from the Kazan Icon of the Mother of God, and images of saints were discovered under the whitewash. The wall paintings of the church were lost under layers of paint.

Among the monastery buildings, the corner tower, fragments of the wall, the rector's house, the refectory, and the guesthouse have survived. The necropolis was partially covered by asphalt. In the summer of 2001, gifts from parishioners to the Kazan icon were stolen by a local drug dealer. However, the Assumption Church is being restored through the efforts of the rector and parishioners and is one of the most visited in the city. In 2004, the revival of the monastery began.