The Shirvan era greatly influenced Baku and the remainder of present-day Azerbaijan. Between the 12th and 14th centuries, massive fortifications were built in Baku and the surrounding towns. The Maiden Tower, the Ramana Tower, the Nardaran Fortress, the Shagan Castle, the Mardakan Castle, the Round Castle and also the famous Sabayil Castle on the island of the Bay of Baku date from this period. The city walls of Baku were also rebuilt and strengthened.