The Holy Roman Empire (HRE) is a very loose Constitutional Monarch-led union which today consists of Germany, The Czech Republic, and Austria. The last member outside of the ones mentioned was Italy which Napoleon declared independent of the HRE on June 3rd, 1812.
Around 900, autonomous stem duchies (Franconia, Bavaria, Swabia, Saxony and Lotharingia) reemerged in East Francia. After the Carolingian king Louis the Child died without issue in 911, East Francia did not turn to the Carolingian ruler of West Francia to take over the realm but instead elected one of the dukes, Conrad of Franconia, as Rex Francorum Orientalium. On his deathbed, Conrad yielded the crown to his main rival, Henry the Fowler of Saxony (r. 919–36), who was elected king at the Diet of Fritzlar in 919. Henry reached a truce with the raiding Magyars, and in 933 he won a first victory against them in the Battle of Riade.
Present Day Edit
The HRE gradually declined after the Napoleonic Wars in which Emperor Napoleon limited the HRE's authority to Prussia and Austria, with the other German states becoming French puppets. WW1 and WW2 both nearly led to the Allies ending the HRE, however they feared provoking another war after WW1 and again after WW2. After the dissolution of Czechoslovakia in 1992 The Czech Republic joined the HRE do to popular demand. This means that today the HRE is not as mighty as it historically was, however it is still one of the strongest entities on Earth (it's in an odd position of both not being a nation and being a nation).