This 16th-century cathedral (built 1516) is the oldest free-standing building in Yaroslavl; inside are beautiful frescoes from the time of its construction. Designed by an Italian architect, the church combines traditional Russian with Italianate styles, such as its arched loggia. You can get a good view of Yaroslavl from its bell tower.
Note that the cathedral is closed to the public on rainy days to protect its delicate frescoes from moisture.