It's Milan Obrenovich, King Serbia from 1868 to 1889. Abdicated one day, gave the job to his son, moved to Paris, and retired. But you can't keep a good king down - he was back in the government business a few years later, then retired in Vienna, where he died in 1901.

Fifty BILLION. I can imagine asking someone to break this for quarters.

"Quarters? Plural?"