|Serpukhov Kremlin (picture by Nikolay Burdykina)|
Vladimir the Bold built the first building called "the kremlin." Vladimir was prince of Serpukhov, a district established in 1349 to protect Moscow from invasion from the south. Vladimir was given the rule of Serpukhov by his cousin, Dmitry Donskoy, the Prince of Moscow. (To be frank, both cousins were only a few years old, and so the arrangements were made by regents.)
In 1374, grown up and able to act on his own, Vladimir built the first structure to be called "kremlin" out of oak; it has been rebuilt since with stone (see picture), though now it is considered merely a ruin.
Vladimir was a great military commander, successfully defending Russia against her foes, mostly Mongols. He died in 1410, leaving seven sons behind. His great-grandson was Ivan the Great. Ivan the Great had no liking for the princes of Serpukhov, despite his distant familial connection to them, and exiled them to Lithuania.