Roman Empire (officially: Impero d'Italia) is a contitutional monarchy located in southern Europe, consisting of Northern Apennine Peninsula, separated to the north by the Alps and Dynaric Alps to the East. It is a democratic unitary state with the title of Emperor being herditary, but having only representative functions, with real power. It was around 1000 BCE. In the beginnnig it expanded through conquest, but when it controlled all of Italy, the conqest was halted, because of increasing difficulties to rule the empire.
Area: 240 000 sq km
Population: 120 mln people
Roman Empire is a state very homogenous ethincally. 95% of citizens speak Italian. Some inhabitants of the eastern provinces speak Croatian, but it is slowly going extinct, as Croatian area was a part of Roman Empire since over 2000 years ago and Croats are very well integrated into the population. Original language of Roman Empire was Latin, but through thousands of years of evolution, it changed hugely and evolved into a form very different form its origin.
Roman Empire always was and still is a seat of pope. For most time, pope's power was limited to representative and international functions, but it still had large effect on population, which is still dominated by the catholics. Italy always had a relatively large Jewish minority just as most of Europe.
Other religions: 6%