Suleiman I, known as Suleiman the Magnificent in the West and Kanunî Sultan Süleyman in his realm, was the longest-reigning Sultan of the Ottoman Empire from 1520 until his death in 1566. Under his rule, the Ottoman state ruled over at least 25 million people - what many scholars call the apex of the Empire. Suleiman and his military were a force to be reckoned with - shortly after ascending the throne, he began campaigns against Christian powers of Europe and the Mediterranean. Changes made by Suleiman to the Empire included major overhauls of society, education, taxes, and law.