This monastery was founded by one of the most honoured Russian saints, Sergius of Radonezh and it represents one of the major Russian Orthodox sanctuaries. Troitse-Sergieva Lavra played a very important role in the unification of Russian lands with the center in Moscow. According to the legends Sergius of Radonezh gave his blessing to the Moscow grand duke, Dmitry Donskoy, for the battle against the Mongols at Kulikovo in 1380. He also sent with him two monks from the monastery, one of which, Alexandr Peresvet, defeated the strongest Mongol warrior, Temir-Mursa, in a one-to-one battle in front of both armies. The victory inspired the Russian troops that won the fight.

Strategically, Troitse-Sergieva Lavra was a very important fortress that protected Russian capital from the North. But it also was a scientific center where books and chronicles were preserved and created. Nowadays, the monastery is famous for invaluable cultural and spiritual significance. It is one of Russia's most important pilgrimage sites and one of the four Russian Orthodox Complexes that can be called 'Lavra' (meaning the major Orthodox monastery, submitted directly to the Russian Patriarch). One of the most important treasures of Troitse-Sergieva Lavra is Troitsky Sobor (Trinity Cathedral). It is the oldest (1422-1423) and finest of the monastery buildings. Especially for this Cathedral one of the greatest Russian icon painters, Andrei Rublev, wrote the famous icon of Old Testament Trinity (circa 1410, Tretyakov Gallery, Moscow)