齋藤道三
The first Gifu Castle was first built by the Nikaidō clan between 1201 and 1204 during the Kamakura Period. Originally little more than a small fort, it was reconstructed on a much larger scale in the Muromachi period by Saitō Toshinaga (d.1460). Toshinaga had served the title of "shugo" of Mino Province, but due to internal conflicts, the Saitō clan had been supplanted in turn by the Toki clan. The clan's fortunes were restored in the form of an adventurer from Kyoto who assumed the name of Saitō Dōsan. Also known as the "Viper of Mino", Saitō Dōsan ruthlessly overcame his enemies, expelled the Toki clan, and defeated an invasion from neighboring Owari Province led by Oda Nobuhide. Saitō Dōsan was killed in a revolt by his own son, Saitō Yoshiyasu. Although Yoshiyasu showed promise as a ruler, he died at the age of 34, leaving Inabayama Castle to his son Saitō Tatsuoki.