Moscow is the capital city of Russia.
During the Renaissance, it was one of the locations where the Mentor of the Italian Assassins, Ezio Auditore da Firenze, could send his Assassin apprentices for contract assignments, during his effort to rebuild the Assassin Order in Rome.
During his time in Rome, Ezio Auditore sent a team of Apprentices sent to Moscow to keep an eye on Ivan III Vasilevich. They started by investigating the disappearance of Pietro Antonio Solari, a fellow Assassin who had vanished while working as an architect on the Kremlin. They discovered a vault with records that revealed Solari had been murdered by another Italian, known only as "Aristotele".
They decided their best option was try finding Aristotele and began their search at the Kremlin. After having questioned several people, they were directed towards a church, where they eventually found the man they were looking for, Ridolfo Fioravant. Ridolfo revealed to them that Ivan was close to discovering the presence of the Assassin Order, and that he had been forced to deceive him.
The Assassins then decided to make Ivan believe in a cult that did not exist, the Strigolniki Sect. They forged documents and spread them among the population, causing paranoia in the citizens of Moscow. Because of this, Ivan soon gave up on his investigation into the Brotherhood and began investigating the Strigolniki Sect instead.
In 2002, Daniel Cross infiltrated the library of Ivan the Terrible, which was hidden beneath the Bolshoi Theatre in the city. He had posed as a replacement for the Assassin guarding it, and following this, he opened the Prophet's Codex and read Minerva's speech to Warren Vidic via his earpiece, before taking it with him back to Abstergo Industries and killing the Assassin sentry.