The political faction that Sigmar Heldenhammer is the patron deity of is based on what real-world empire?
The Empire (Warhammer) In Games Workshop's "Warhammer Fantasy" fictional universe, The Empire is one of the human political factions and armies, and is featured in many games and novels. In terms of location, language, culture, and society, it is clearly based on the real-world medieval Holy Roman Empire.
Western Roman Empire In historiography, the Western Roman Empire consists of the western provinces of the Roman Empire at any one time during which they were administered by a separate independent Imperial court, coequal with (or only nominally subordinate to) that administering the eastern half. Both "Western Roman Empire" and "Eastern Roman Empire" (or "Byzantine Empire") are modern terms describing "de facto" independent entities; however, at no point did the Romans consider the Empire split into two, but rather considered it a single state governed by two separate Imperial courts out of administrative expediency. The view that the Empire was impossible to govern by one emperor was established by Diocletian following the disastrous civil wars and disintegration of the Crisis of the 3rd century, and was instituted in Roman law by his introduction of the Tetrarchy in AD 285, a form of government which was legally to endure in one form or another for centuries. The Western Court was periodically abolished and recreated for the next two centuries until final abolition by Zeno in 480, by which time there was little effective central control left in the area legally administered by the Western Court.