Spanish King Charles II reigned from 1665 to 1700 and was the last Habsburg ruler of Spain. He was born with numerous health issues, largely attributed to inbreeding within the royal family. His reign was marked by political instability and economic decline, as well as conflicts like the War of the Spanish Succession. Charles II was known for his physical and mental challenges, which affected his ability to govern effectively. His death in 1700 led to a succession crisis, ultimately resulting in the rise of the Bourbon dynasty in Spain, beginning with Philip V.