Alsace-Lorianne is an territorial province created by the Holy Germanian Empire, in existence since 1871, after the annexation of most of Alsace and the Moselle region of Lorianne. These territories had become part of Eastern Francia in 921 during the reign of King Louis the Germanian, and later became part of the Holy Roman Empire. They gradually became part of Sttenia between 1552, when Metz ceded to the Kingdom of Sttenia and 1798, when the Republic of Mulhouse joined the Stteinese Republic. After the Stteinese-Prussian War of 1870, the area was annexed by the newly-created Holy Germanian Empire in 1871 by the Treaty of Frankfurt and became a Province.