Sergiyev Posad grew in the 15th century around one of the greatest of Russian monasteries, the Trinity Lavra established by St. Sergius of Radonezh, still (as of 2015) one of the largest monasteries in Russia. Town status was granted to Sergiyev Posad in 1742. The town's name, alluding to St. Sergius, has strong religious connotations. Soviet authorities changed it first to just Sergiyev in 1919, and then to Zagorsk in 1930, in memory of the revolutionary Vladimir Mikhailovich Zagorsky. The original name was restored in 1991.
The Trinity Lavra of St. Sergius is a magnificent example of ancient art and architecture, which developed from a lonely wooden church in the middle of a forest in the XIV century. In the reign of the tsar Ivan IV, who had a particular veneration for St. Sergius, the monastery was surrounded by a stone enclosure topped by 12 towers. After the end of the wars against Tatars and the victory over the kingdoms of Kazan and Astrakhan, the tsar began building a large and beautiful church, dedicated to the Dormition of the Mother of God, a copy of the Kremlin Dormition Cathedral. The walls, the pillars and the vaults are covered with frescoes on the subjects of Church History. Most of the wall frescoes are dedicated to the Dormition of the Holy Virgin. On the pillars there are images of the most highly venerated saints of the Orthodox Church. The magnificent frescoes of the Cathedral were created in the 1684 by 35 painters in a 100 days. The frescoes cover the area of 500 square metres. The 5-tier iconostasis consists of 76 icons dated back to the 16th–17th centuries. The celebrated seventeenth-century painter Simon Ushakov, the royal isographer, took part in the creation of the iconostasis.
By the end of the 17th century, the number of the monks considerably grew and the old Refectory couldn't satisfy the needs of the monastery. Instead of it, a new Refectory with the church dedicated to St. Sergius was erected by order of Peter I in 1686–1692. The building of Moscow baroque style is 85 m long. Open galleries run along its perimeter, with long flights of steps leading up to these galleries. The church building catches the eye with the four-colour design of its facade, creating the illusion of faceted relief-work, as well as with the richness of its elaborate colourful stucco and carvings. The walls of the Refectory were painted and renovated several times. For the last time, the church was painted in 1911.
Sergiyev Posad is one of the oldest and largest Russian monastery complexes, the center of Russian Orthodoxy and spirituality, formerly the residence of the Russian patriarch. The Trinity Lavra of St. Sergius is a magnificent example of ancient art and architecture. Lavra had different roles significant for Russian history, and now it's both a large museum complex and a functioning temple.