Emperor Charles I, also known as Charles V, was a significant ruler in the 16th century. He was born in 1500 and became the Holy Roman Emperor in 1519. His reign included vast territories across Europe, including Spain, the Netherlands, and parts of Italy. Charles I was known for his efforts to maintain Catholicism during the Protestant Reformation. Charles I faced numerous challenges, including conflicts with France and the Ottoman Empire. He also dealt with internal strife within his empire, particularly from Protestant reformers. In 1556, he abdicated, dividing his empire between his brother Ferdinand I and his son Philip II of Spain.