Its government was an absolute monarchy, backed up by a very powerful Catholic Church.
The Spanish Empire sought to convert the pagan world to Catholicism, sought to exterminate heresy (Protestantism) in Europe, tried to unite Europe against the Turks, and milked the New World as much as possible for all the gold and silver it could get. In the process it established the biggest empire the world had ever seen. The Habsburgs ( Emperor Charles V and his descendants) had a claim to the Netherlands through various marriages. The Netherlands became Protesant, and this resulted in a war against Spanish oppression that lasted for 80 years. This Dutch war of independence bankrupted the Spanish Empire and it never really recovered after this.
The Spanish Inquisition was notorious. It mercilessly persecuted Jews, Moors and people who had recently converted (as it was thought that their conversions were not sincere). People were burned wholesale in auto da fes which drew huge audiences. Spanish society was very strict and hierarchical, but even so the Spanish people produced wonderful music and art.
