of the Hōjō clan was the eighth shikken (officially regent of the shōgun, but de facto ruler of Japan) of the Kamakura shogunate (reigned 1268–84), known for leading the Japanese forces against the invasion of the Mongols and for spreading Zen Buddhism. He was the eldest son of Tokiyori, fifth shikken (regent) of the Kamakura shogunate and de facto ruler of Japan. From birth, Hojo was seen as the tokuso (head) of the clan Hōjō and rigorously groomed to become his father's successor. In 1268 AD, at the age of 18, he became shikken himself. Tokimune was known to rule with an iron fist and also eventually monopolized at one point all three titles of power, namely holding the offices of tokusō (head of clan), since birth, and rensho (vice regent). During his lifetime, the seats of power of the Japanese Emperor, Imperial Regent (sesshō), Imperial Chief Advisor (kampaku), and the shōgun had all been completely marginalized by the Hōjō shikken. Life Immediately upon his ascension as shikken, Tokimune was faced with a national crisis. The Mongol emperor, Kublai Khan, sent an envoy with the demand that Japan enter into a "tributary relationship" with the Mongols or face invasion and conquest. While many in the Japanese government, including members of the royal family, urged that a compromise be reached, the regent defiantly rejected the Mongol demand and sent back the headless bodies of the emissaries. Because of his influence, Zen Buddhism became firmly established in Kamakura, then later in Kyoto and in the whole of Japan, especially among the warrior class. In 1271, he banished Nichiren to Sado Island. After the war with the Mongols ended, Tokimune turned his attention to other matters, like practicing Zen meditation and building Buddhist shrines and monasteries, such as the one at Engaku-ji as a memorial to those samurai who had died defeating the Mongols. As a teen and young man, he had been an advocate of the Ritsu sect of Buddhism, but converted to Zen at some point before the invasion. He was so committed to his faith that he "took the tonsure and became a Zen monk" on the day that he died. Defiance of Mongols The Mongols had sent a threatening letter and emissaries to Japan in January 1268, and after discussion, Tokimune decided to have the emissaries sent back with no answer. The Mongols sent more emissaries time and time