Oda Nobunaga was a powerful Japanese daimyo (feudal lord) during the late 16th century. He played a crucial role in the unification of Japan, which was fragmented into many warring states. Nobunaga is known for his innovative military strategies and use of firearms, which helped him defeat larger armies. Nobunaga's reign began in 1551 and lasted until his death in 1582. He was a patron of the arts and supported the spread of Christianity in Japan. His legacy continued through his successors, particularly Toyotomi Hideyoshi and Tokugawa Ieyasu, who completed the unification process.