Kings of Spain

This is a list of Spanish Heads of State; that is, kings and presidents that governed the country of Spain in the modern sense of the word. The forerunners of the Spanish throne were the following:

These lineages were eventually united by the marriage of Ferdinand II of Aragon and Isabella I of Castile. Although their kingdoms continued to be separate, with their personal union they ruled them together as one dominion. Ferdinand also conquered the southern part of Navarre and annexed it to what was to become Spain. Isabella left her kingdom to her daughter Joanna of Castile. Ferdinand served as her regent during her insanity; though rebuffed by the Castilian nobility and replaced by Joanna's husband Philip the Handsome, he resumed his regency after Philip's death. In 1516, after Ferdinand II's death, his daughter Joanna inherited the kingdom of Aragon, but was kept prisoner at Tordesillas as insane. As Joanna's son, the future Holy Roman Emperor Charles V, did not want to be merely a regent, he was proclaimed king of Castile and Aragon jointly with his mother in Brussels. Subsequently, Castilian and Aragonese Cortes alleged oath to him as co-king with his mother. Upon her death, he became sole King of Castile and Aragon, and the thrones were thereafter united permanently.

During the First Spanish Republic (1873–74), Spain had heads of state known as the President of the Executive Power. It is only during the Second Spanish Republic (1931–39), however, that the official title of President of Spain (or President of the Republic) existed. Today, Spain is a constitutional monarchy, and there is thus no person holding the title of President of Spain. However, the Prime Minister holds the official title of President of the Government.

...
Wikipedia