Charles IV was King of Spain from 14 December 1788 until his abdication on 19 March 1808.
Charles was the second son of Charles III

Charles III of Spain

Charles III was the King of Spain and the Spanish Indies from 1759 to 1788. He was the eldest son of Philip V of Spain and his second wife, the Princess Elisabeth Farnese...

 and his wife Maria Amalia of Saxony

Maria Amalia of Saxony

Maria Amalia of Saxony was a German princess from the House of Wettin and was the wife of Charles III of Spain; she was the Queen consort of Naples and Sicily from 1738 till 1759 and then Queen consort of Spain from 1759 until her death in 1760...

. He was born at Naples

Naples

Naples is a city in Southern Italy, situated on the country's west coast by the Gulf of Naples. Lying between two notable volcanic regions, Mount Vesuvius and the Phlegraean Fields, it is the capital of the region of Campania and of the province of Naples...

(11 of November, 1748), while his father was king of the Two Sicilies. His elder brother Don Felipe was passed over for the two thrones as mentally retarded

Mental retardation

Mental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...

 and epileptic

Epilepsy

Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...

. In Naples and Sicily he was styled as the Prince of Taranto.

Charles had inherited a great frame and immense physical strength from the Saxon line of his mother, granddaughter of August the Strong.