Tenbun was an era from 7/29 of 1532 to 10/23 of 1555 (based on the Japanese lunisolar calendar) in the Sengoku period.
The change from the prior era known as Kyōroku occurred upon request of Ashikaga Yoshiharu owing to war and calamities.
During this era, Gonara (reign: 1526-1557) served as the 105th emperor; Ashikaga Yoshiharu (reign: 1522-1546), served as the twelfth shōgun and Ashikaga Yoshiteru (reign: 1546-1565) as the thirteenth shōgun of the Muromachi bakufu.
The Battle of Yamashina-Hongan Temple erupted in Kyōto, in which the allied forces of Hosokawa Harumoto, Rokkaku Sadayori, and adherents of the Nichren sect of Buddhism (known as the Hokke) fought against members of the Jōdō-shinshū sect of the Hongan Temple, resulting in the burning of the temple.
At the Collapse at Moriyama (Moriyama kuzure), Matsudiara Kiyoyasu, the seventh head of the Matsudaira clan of Mikawa Province and lord of Okazaki Castle, was slayed by one of his retainers while on base in Moriyama in Owari Province.
In the Tenbun-Hokke Conflict (Tenbun-Hokke no ran), monks from the Enryaku Temple prevailed in battles against adherents of the Hokke school of the Nichren sect, burning down twenty-one of their temples in Kyōto.
Takeda Harunobu (later known as Takeda Shingen), ousted his father, Takeda Nobutora, succeeding him as the military governor of Kai Province and as head of the clan. Harunobu then launched an invasion of Shinano Province.
A Portuguese ship became stranded on Tanegashima, an island off of the southern tip of Kyūshū. This led to the introduction of the arquebus to Japan.
Hōjō Ujiyasu, the sengoku daimyō of Sagami Province, significantly expanded his domain after prevailing against the Imagawa at the Second Conflict at Katō, a battle for control of a strategic area to the east of the Fuji River near the domains of the Takeda, the Imagawa, and the Hōjō, and at the Battle of Kawagoe Castle at a vital location in Musashi Province and defended by the Yamanouchi-Uesugi family.
Ashikaga Yoshiteru became the thirteenth shōgun of the Muromachi bakufu.
Nagao Kagetora (later known as Uesugi Kenshin) took over as head of the clan from his older brother, Nagao Harukage, and entered Kasugayama Castle in Echigo Province.
Oda Nobunaga of Owari Province, wed Nōhime, the daughter of Saitō Dōsan, the sengoku daimyō of Mino Province.
At the Battle of Eguchi in Settsu Province, Miyoshi Nagayoshi defied the wishes of his main patron, Hosokawa Harumoto, by fighting against Miyoshi Masanaga, who perished in the battle.
Fearing an attack by Nagayoshi, Harumoto and members of the shōgun family fled Kyōto and could not recover from their inferior position, bringing the Hosokawa administration to an end.
Francisco de Xavier, a Catholic priest from Spain, arrived by Chinese junk to Satsuma Province in Kyūshū.
The Imagawa of Suruga seized Anjō Castle in Mikawa Province from Oda Nobuhide of Owari Province. Nobuhide’s eldest illegitimate son, Oda Nobuhiro, and lord of the castle, was apprehended and the Oda clan shut out of Mikawa.
Imagawa Yoshimoto took control of the territory of the Matsudaira in Mikawa Province. Takechiyo (later known as Tokugawa Ieyasu) was sent to Sunpu as a hostage of the Imagawa.
At the Collapse on the Second Floor, Õtomo Yoshiaki, the military governor of Bungo Province in Kyūshū, and his family members were attacked by retainers on the second floor of their residence. Yoshiaki incurred serious injuries and died several days later.
At the Tainei Temple Incident, Ōuchi Yoshitaka, the sengoku daimyō of Suō Province, was attacked by forces under Sue Harukata, the deputy military governor. Yoshitaka killed himself after fleeing to the Tainei Temple in Nagato Province, leading to the elimination of the Ōuchi clan.
At the Battle of Itsukushima, Mōri Motonari defeated Sue Harukata at Itsukushima in Aki Province, whereupon Harukata took his own life. Thereafter, Motonari annexed the former territory of the Ōuchi.