Short answers, pulled from the story.
Sergius of Radonezh built a wooden church on Makovets Hill in 1337 to honor the Holy Trinity. This small structure became the seed for what would grow into Russia's most important monastery.
Andrei Rublev and Daniil Chyorny decorated this cathedral with frescoes that remain some of medieval Russia's greatest icon paintings. Their work included the central piece known as The Trinity, now displayed within the cathedral's iconostasis.
Orthodox monks led by chronicler Avraamy Palitsyn defended the complex against Polish troops from September 1609 to January 1611. This celebrated siege lasted 16 months while the monastery served as a strategic stronghold.
Empress Elizabeth conferred Lavra status upon the cloister in 1744, making the metropolitan of Moscow also its Archimandrite. She annually walked barefoot from Moscow to the monastery accompanied by her secret spouse Alexey Razumovsky.
Divine service resumed at the Assumption Cathedral on the 16th of April 1946 after decades of closure. Joseph Stalin granted temporary tolerance allowing the Lavra to return to the Russian Orthodox Church in 1945.