Short answers, pulled from the story.
The founding year of the Tretyakov Gallery is considered to be 1856, when the Muscovite merchant Pavel Mikhailovich Tretyakov purchased two paintings by Russian artists: Temptation by Nikolay Shilder and Skirmish with Finnish Smugglers by Vasily Khudyakov. Tretyakov's aim was to create a collection that would grow into a museum of national art.
The Tretyakov Gallery collection contains more than 130,000 exhibits. These range from the ancient Byzantine icon the Theotokos of Vladimir to Wassily Kandinsky's Composition VII and Kazimir Malevich's Black Square.
The facade was designed by the painter Viktor Vasnetsov in a Russian fairy-tale style, based on his drawings produced between 1900 and 1903. It was built between 1902 and 1904, with construction managed by architect A. M. Kalmykov.
In the summer of 1941 the collection was packed and transported on a train of 17 wagons from Moscow to Novosibirsk for safekeeping. The gallery did not reopen in Moscow until the 17th of May 1945, after the war ended.
In June 2023 the icon was transferred to Moscow's main cathedral on the personal order of Russian President Vladimir Putin, despite the Tretyakov Gallery's protests. The museum had refused an earlier request from the Russian Orthodox Church in May 2023.
The Tretyakov Gallery attracted 894,374 visitors in 2020, down 68 percent from 2019 due to the COVID-19 pandemic. Despite the decline, the gallery ranked 13th on the list of most-visited art museums in the world that year.