Wikipedia:
He was Grand Prince of the Hungarians (997–1000) and the first King of Hungary (1000–1038). He greatly expanded Hungarian control over the Carpathian Basin during his lifetime, broadly established Christianity in the region, and he is generally considered to be the founder of the Kingdom of Hungary. Pope Gregory VII canonized Stephen I, together with his son, Saint Emeric of Hungary and Bishop Gerard of Csanád, on 20 August 1083, becoming one of the most popular saints in Hungary, and his birthday is celebrated as a state holiday commemorating the foundation of the nation.
The king's right hand, known as "The Holy Right," is kept as a relic. His body was mummified after his death, but the tomb was opened and his hand was separated some years later. Except for this, only some bone fragments remained (which are kept in churches throughout Hungary). Hungarian Catholics honor the first king of their country on annual processions, where the "Holy Right" is exhibited.