The monarchy comprises the reigning monarch, his or her family, and the royal household organization which supports and facilitates the monarch in the exercise of his duties and prerogatives. The Spanish monarchy is represented by King Felipe VI, his wife Queen Letizia, and their daughters Leonor, Princess of Asturias, and Infanta Sofía.
The Spanish Constitution of 1978 re-established a constitutional monarchy as the form of government for Spain. The 1978 constitution affirmed the role of the King of Spain as the personification and embodiment of the Spanish State and a symbol of Spain's enduring unity and permanence. Constitutionally, the king is the head of state and commander-in-chief of the Spanish Armed Forces. The constitution codifies the use of royal styles and titulary, royal prerogatives, hereditary succession to the crown, compensation, and a regency-guardianship contingency in cases of the monarch's minority or incapacitation. According to the constitution, the monarch is also instrumental in promoting relations with the "nations of its historical community". The King of Spain serves as the president of the Ibero-American States Organization, purportedly representing over 700,000,000 people in twenty-four member nations worldwide. In 2008, Juan Carlos I was considered the most popular leader in all Ibero-America.
The Spanish monarchy has its roots in the Visigothic Kingdom founded in Spain and Aquitania in the 5th century, and its Christian successor states which fought the Reconquista following the Umayyad invasion of Hispania in the 8th century. A dynastic marriage between Isabella I of Castile and Ferdinand II of Aragon united Spain in the 15th century. The last pretender of the Crown of the Byzantine Empire, Andreas Palaiologos, sold his imperial title to Ferdinand II of Aragon and Isabella I of Castile before his death in 1502.
The Spanish Empire became one of the first global powers as Isabella and Ferdinand funded Christopher Columbus's exploratory voyage across the Atlantic Ocean. This led to the discovery of America, which became the focus of Spanish colonization.