According to Biography.com, Frederick the Great was called an enlightened despot because his mother raised him with the values and education of the Enlightenment, and as ruler of Prussia, he sought to instill these values in government and society. His enlightened reforms included religious toleration, partial freedom of the press and reformations of the military and justice systems.
During Frederick's childhood, his mother hired tutors who taught him French culture, poetry and Roman and Greek classical literature. However, his father insisted he study military and political matters. At one point, when Frederick and a friend ran away from his father's strict regime, his father had his friend beheaded and forced Frederick to watch. When his father died, Frederick became both a military genius and a patron of Enlightenment ideals. As part of his revamping of the justice system, Frederick forbade torture and established Prussia's first criminal code. To strengthen the economy, he lowered internal duties, imposed protective tariffs and stimulated trade by building canals.
Frederick also became known as a patron of the sciences and the arts. He was a talented musician himself, and even wrote flute sonatas. At one point he corresponded with Voltaire, one of the intellectual leaders of the Enlightenment. He encouraged the Berlin Academy in its scientific work and commissioned architects to build elaborate structures with the aim of establishing Berlin as a cultural capital.