Although the ancient capital of the province is Shimonoseki, Hagi was usually the seat of the fief. Nagato was ruled by the Mori clan before and after Sekigahara.
Choshu (長州) is the commonly used abbreviation for the Nagato province of ancient Japan.
In 1871 with the abolition of feudal domains and the establishment of prefectures (Haihan Chiken) after the Meiji Restoration, the provinces of Nagato and Suo were combined to eventually establish Yamaguchi prefecture.
But many of Choshu'ssamurai refused to accept this decision, and a military coup in 1864 brought to power, as the daimyo's counselors, a group of men who had originally led the radical antiforeign movement.
Choshu became the centre for discontented samurai from other domains who were impatient with their leaders' caution.
In 1869 the lords of Satsuma, Choshu, Tosa, and Saga were persuaded to return their lands to the throne.