Since becoming director of the Czech National Gallery three years ago this month, Jiří Fajt has secured exhibitions by major international artists and helped make its numerous buildings in the capital more accessible to the public. Our tour of “his Prague” begins at the Convent of St. Agnes of Bohemia on the edge of the Old Town. It houses the National Gallery’s impressive medieval collection and was headed by the Prague-born Fajt himself in the late 1990s.