was a Japanese Tendai

Tendai

is a Japanese school of Mahayana Buddhism, a descendant of the Chinese Tiantai or Lotus Sutra school.Chappell frames the relevance of Tendai for a universal Buddhism:- History :...

 Buddhist monk of the Azuchi-Momoyama

Azuchi-Momoyama period

The came at the end of the Warring States Period in Japan, when the political unification that preceded the establishment of the Tokugawa shogunate took place. It spans the years from approximately 1573 to 1603, during which time Oda Nobunaga and his successor, Toyotomi Hideyoshi, imposed order...

 and early Edo

Edo period

The , or , is a division of Japanese history which was ruled by the shoguns of the Tokugawa family, running from 1603 to 1868. The political entity of this period was the Tokugawa shogunate....

 periods. He achieved the rank of Daisōjō, the highest rank of the priesthood.
His Buddhist name was first , which he changed to Tenkai in 1590. Also known as , he died in 1643, and was granted the posthumous title of in 1648.

Tenkai was at Kita-in

Kita-in

is a Buddhist temple located in the city of Kawagoe in Saitama, Japan. It is noted for its main hall, which was part of the original Edo Castle, and the statues of 540 Rakan, disciples of the Buddha.- Origins and history :...

 (then written 北院) in Kawagoe

Kawagoe, Saitama

is a city located in Saitama Prefecture, Japan, and is about a 30-minute train ride from Ikebukuro in Tokyo.As of July 1, 2011, the city has an estimated population of 343,926...

 in 1588, and became abbot in 1599. He was on the staff of Tokugawa Ieyasu

Tokugawa Ieyasu

 was the founder and first shogun of the Tokugawa shogunate of Japan , which ruled from the Battle of Sekigahara  in 1600 until the Meiji Restoration in 1868. Ieyasu seized power in 1600, received appointment as shogun in 1603, abdicated from office in 1605, but...

, and served as a liaison between the Tokugawa Shogunate

Tokugawa shogunate

The Tokugawa shogunate, also known as the and the , was a feudal regime of Japan established by Tokugawa Ieyasu and ruled by the shoguns of the Tokugawa family. This period is known as the Edo period and gets its name from the capital city, Edo, which is now called Tokyo, after the name was...

 and the Imperial Court in Kyoto

Imperial Court in Kyoto

thumb|left|350px|Front view of Kyoto imperial palaceImperial Court in Kyoto was the nominal ruling government of Japan from 794 AD until the Meiji Era, in which the court was moved to Tokyo and integrated into the Meiji government....

. One of his projects was the rebuilding of Enryaku-ji

Enryaku-ji

thumb|300px|Konpon Chū-dō , Enryaku-ji's main hall is a Tendai monastery located on Mount Hiei in Ōtsu, overlooking Kyoto. It was founded during the early Heian period. The temple complex was established by Saichō , also known as Dengyō Daishi, who introduced the Tendai sect of Mahayana Buddhism...

, which had been devastated by Oda Nobunaga

Oda Nobunaga

was the initiator of the unification of Japan under the shogunate in the late 16th century, which ruled Japan until the Meiji Restoration in 1868. He was also a major daimyo during the Sengoku period of Japanese history. His opus was continued, completed and finalized by his successors Toyotomi...

. He also revitalized Kita-in, and changed the characters of its name to 喜多院. Nearing death in 1616, Ieyasu entrusted Tenkai with his last will regarding matters of his funeral and his posthumous name. Tenkai selected gongen

Gongen

During the era of shinbutsu shūgō , in Japan a During the era of shinbutsu shūgō (religious syncretism of kami and buddhas), in Japan a During the era of shinbutsu shūgō (religious syncretism of kami and buddhas), in Japan a ( was believed to be a Japanese kami which was really just the local...

rather than myōjin, and after death Ieyasu became known as Tōshō Daigongen.

Tenkai continued to serve as a consultant to the next two Tokugawa shoguns. In 1624, retired shogun Tokugawa Hidetada

Tokugawa Hidetada

was the second shogun of the Tokugawa dynasty, who ruled from 1605 until his abdication in 1623. He was the third son of Tokugawa Ieyasu, the first shogun of the Tokugawa shogunate.-Early life :...

 and ruling shogun Tokugawa Iemitsu

Tokugawa Iemitsu

Tokugawa Iemitsu was the third shogun of the Tokugawa dynasty. He was the eldest son of Tokugawa Hidetada, and the grandson of Tokugawa Ieyasu. Iemitsu ruled from 1623 to 1651.-Early life :...

 asked him to establish Kan'ei-ji

Kan'ei-ji

-External links:** * National Diet Library: ; *...

, a Buddhist temple to the northeast of Edo Castle

Edo Castle

, also known as , is a flatland castle that was built in 1457 by Ōta Dōkan. It is located in Chiyoda in Tokyo, then known as Edo, Toshima District, Musashi Province. Tokugawa Ieyasu established the Tokugawa shogunate here. It was the residence of the shogun and location of the shogunate, and also...

 in Ueno

Ueno, Tokyo

is a district in Tokyo's Taitō Ward, best known as the home of Ueno Station and Ueno Park. Ueno is also home to some of Tokyo's finest cultural sites, including the Tokyo National Museum, the National Museum of Western Art, and the National Science Museum, as well as a major public concert hall...

.

There are several theories concerning his early life. Some fiction writers postulate that he was in actuality Akechi Mitsuhide

Akechi Mitsuhide

, nicknamed Jūbei or called from his clan name and title, was a samurai who lived during the Sengoku period of Feudal Japan.Mitsuhide was a general under daimyo Oda Nobunaga, although he became infamous for his betrayal in 1582, which led to Nobunaga's death at Honno-ji...

. It is not certain whether Mitsuhide died at the Battle of Yamazaki or not, and some suppose that he survived and began a new life as the priest Tenkai.

In the game Sengoku Basara 3, the character Tenkai is portrayed as a cryptic monk who speaks in riddles and wields twin scythes. As with the rumor above, Tenkai is actually a re-skinned model of Akechi Mitsuhide, from the game's predecessor.