King Friedrich Wilhelm IV of Prussia reigned from 1840 to 1861. He was known for his romantic ideals and his vision of a united Germany. Friedrich Wilhelm IV was a member of the Hohenzollern dynasty and was the son of Friedrich Wilhelm III. His reign was marked by a mix of conservative policies and attempts at reform. During his rule, Friedrich Wilhelm IV faced significant political challenges, including the Revolutions of 1848 that swept across Europe. He initially promised a constitution and reforms but later rejected the idea of a unified Germany under his leadership. His reluctance to embrace change ultimately led to his decline in popularity.