The most noteworthy building on Toompea is the limestone citadel, built in the first half of the 13th century, when Tallinn was seized by Denmark followed by the Teutonic Knights. In the Middle Ages, the Small Citadel in the SW part ofToompea was the headquarters of the viceroy and guards, while the remaining forces kept the Main Citadel, including the bishop and the king's vassals. Three corner towers remain: Tall Hermann, Pilsticker and Landskrone. The newer buildings mostly stand on older foundations.
In the 18th century, Russian czarist authorities decided to transform the citadel into a showy palace. Catherine II ordered the reconstruction of three-quarters of the east wing into a governmental building with a baroque facade. The Small Citadel, repeatedly reconstructed, is known today as Toompea Castle and is home to parliament and parliamentary offices. The Estonian government cabinet and the prime minister meet in the Stenbock house (named for its former Baltic German owner), which was redesigned and converted accordingly.
The Tall Hermann tower, which dates from the 14th century, is the symbol of Tallinn and all of Estonia. Historically, the flag of whichever nation ruled Estonia invariably has fluttered from its heights. Since 1991, the national blue-black-and-white colours have once again flown on Tall Hermann.