was a Japanese daimyo

Daimyo

is a generic term referring to the powerful territorial lords in pre-modern Japan who ruled most of the country from their vast, hereditary land holdings...

 of the early Edo period

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....

. He was the eldest son of Date Masamune

Date Masamune

was a regional strongman of Japan's Azuchi-Momoyama period through early Edo period. Heir to a long line of powerful daimyo in the Tōhoku region, he went on to found the modern-day city of Sendai...

, born in 1596 by Lady Iisaka (a concubine). Coming of age while living with Toyotomi Hideyoshi

Toyotomi Hideyoshi

was a daimyo warrior, general and politician of the Sengoku period. He unified the political factions of Japan. He succeeded his former liege lord, Oda Nobunaga, and brought an end to the Sengoku period. The period of his rule is often called the Momoyama period, named after Hideyoshi's castle...

, he received a character from Hideyoshi's name and took the adult name of Hidemune. Hideyoshi also granted him the court rank of and the title of ji-jū, appointing the young Hidemune as a page to his own son Toyotomi Hideyori

Toyotomi Hideyori

was the son and designated successor of Toyotomi Hideyoshi, the general who first united all of Japan. His mother, Yodo-dono, was the niece of Oda Nobunaga....

. After Hideyoshi's death in 1600, he was made a hostage at the residence of Ukita Hideie

Ukita Hideie

was the daimyo of Bizen and Mimasaka provinces , and one of the council of Five Elders appointed by Toyotomi Hideyoshi. Son of Ukita Naoie, he married Gohime, a daughter of Maeda Toshiie...

.

Though he was Masamune's eldest son, Hidemune was born by a concubine, and therefore could not be the successor to the Sendai Domain

Sendai Domain

was a Japanese domain of the Edo period. Most of its holdings were contiguous, covering all of modern-day Miyagi Prefecture, small portions of southern Iwate Prefecture, and a portion of northeastern Fukushima Prefecture. The domain's capital, and the ruling family's castle, were located in what...

, which his father ruled. Masamune therefore considered the possibility of having Hidemune start a branch family. This was made possible in 1614, when father and son took part in the Osaka Campaign: Hidemune received the 100,000 koku

Koku

The is a Japanese unit of volume, equal to ten cubic shaku. In this definition, 3.5937 koku equal one cubic metre, i.e. 1 koku is approximately 278.3 litres. The koku was originally defined as a quantity of rice, historically defined as enough rice to feed one person for one year...

 Uwajima Domain

Uwajima Domain

The was a feudal domain in Iyo Province of Japan during the Edo period. It was ruled from 1608 to 1613 by the Tomita clan. After a brief period as Tokugawa-controlled tenryō territory, the domain passed into the hands of the Date clan. The founder was Date Hidemune , first-born son of Date Masamune...

 which 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...

granted to Masamune. Hidemune immediately entered his new fief as daimyo, and ruled until his retirement in Meireki 3 (1657).