Hojo Tokimune ( June 5 1251 April 20 1284) of the Hojo clan was the eighth shikken (officially regent (of shogun) but de facto ruler of Japan) of the Kamakura shogunate (reigned 126884) known for leading the Japanese forces against the invasion of the Mongols and for spreading Zen Buddhism and by extension Bushido among the warrior class. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
The answer to this question is:
Office Holder