Origin
The Taira were in many ways similar to their rivals, The Minamoto. They were off shoots of the Imperial family, declassed and given a new surname. Many Emperor bestowed the Taira surname to royalties low on the rung, and thus the Taira clans are named after their imperial sire e.g. Nimyo Heishi, a Montoku Heishi, and a Koko Heishi with "Hei" being the Alternate Character Reading of the surname Taira, and Heishi means "Taira clan/clansman."' The most famous of these is the warrior clan Kanmu Heishi (named after Emperor Kanmu, who started the Heian Period in the first place) whose main branch is known as the Heike (meaning "the Taira family").notePrince Takamochi, a great-grandson or grandson of Emperor Kanmu, was bestowed the Taira surname, and his clan set up shop in the eastern provinces. A familial feud between his eldest son and his grandson by a younger son somehow snowballed into a rebellion as said grandson, Taira no Masakado, conquered several provinces and allegedly proclaimed himself as Emperor.note It took three generals, Minamoto no Tsunetomo, Taira no Sadamori, and Fujiwara no Hidesatonote to defeat him. This conflict had little immediate effect, but huge ramification for the next centuries: the descendants of Tsunemoto and Sadamori respectively became the Seiwa Genji and the Ise Heishi i.e. the Heike. Masakado became one of the three great angry spirits of Japan, and eventually became a patron deity of what would become Tokyo.
Rise of the Taira
For several generations, nothing particularly spectacular happened to the clan. The Taira clansmen lived in and governed the provinces, which means they were somewhat wealthy but still nobody in the eyes of the nobles in the capital. Meanwhile, the Fujiwara regency reached its golden age, and the Seiwa Genji held greater prestige thanks to allying with the Fujiwara and winning several wars in the East.The family's fortune changed when political power shifted from the Fujiwara regency to the "cloistered rule" of ex-Emperor, and the Minamoto had several major fuckups. When Minamoto no Yoshichika, firstborn of the legendary Minamoto no "Son of Hachiman" Yoshiie, rebelled and his father failed to suppress him, it was Taira no Masamori who quelled the rebellion. Taira no Tadamori, Masamori's son, became a loyal supporter of the abdicated Emperor Shirakawa, the one who actually held supreme power in Japan. Tadamori's victories against pirates allowed him to tap into the ludicrous underground trade with Song China. The accumulated wealth and prestige over these two generations allowed the ascendancy of Kiyomori, son and heir of Tadamori.
Age of the Heike
Kiyomori rose to the position of daijō daijin (which translates to great minister of state) following his victories in the Hōgen Disturbance of 1156 and the Heiji Rebellion.He then managed to enthrone his infant grandson as Emperor Antoku in 1180, an act which led to the foundation of the first Samurai dominated government, as well as the Genpei War, the war that shook up Japan for good. Kiyomori's sons, the last of the head Kanmu branch, were eventually defeated by the 6 armies of Minamoto no Yoritomo at the Battle of Dan-no-ura, ending the Genpei War in the Minamoto's favor. The Taira would have the last laugh, however, when the Hojo regency began.note
They were one of the Four Great Houses, alongside the Minamoto, Fujiwara, and Tachibana clans. The Oda clan (as in Oda Nobunaga) claimed descent.
