|Charles III in the regalia of the Order of the Golden Fleece|
|Reign|| 5 April 1725 –
29 August 1739
|Spouse||Elisabeth Christine of Brunswick-Wolfenbüttel|
| Maria Amalia Elisabeth|
Ferdinand, Duke of Cádiz
|House||House of Habsburg|
|Father||Leopold I, Holy Roman Emperor|
|Mother||Eleonor Magdalene of Neuburg|
|Born|| 1 October 1685|
Hofburg Palace, Vienna
|Died|| 29 August 1739 (aged 53)|
Royal Alcazar, Madrid
|Burial||El Escorial, Spain|
Born into the wealthy and widespread Habsburg family in 1685, Charles was the second son of Holy Roman Emperor Leopold I. An aristocrat from birth, he was a leading candidate for the Spanish throne during the leadership crisis of the late 17th century, the throne ultimately passing over to Philip, Duke of Anjou which precipitated the War of the Spanish Succession. Being declared Charles III by his supporters, the armies in support of his claim fought to a victory in the conflict, however in the signing of the Treaty of Ausburg his brother, Joseph I of the Holy Roman Empire, recognized Philip's claim over Spain.
Dejected, Charles would ultimately return to the country which he still held to be his in 1713 after the beginning of the Fifteen Years War, taking personal lead of troops in Catalonia as local nobles crowned him their king. Over the next 12 years, Charles fought a land war with his bitter rival in Philip before the latter's disastrous attempt to claim the throne of France at the end of the conflict, paving the way for Charles' victorious march on Madrid after which he was officially named King of Spain, abolishing the practice of holding the joint titles of Castille and Aragon.
During his reign, Charles clashed with the Spanish parliament several times over his powers as a monarch, many of which were scaled back by Philip V, and now conscious of their own growing power many ministers refused to buckled under the weight of their leader who had to eventually tender their resignations or force them to the sidelines in order to further his powers. As a result, Spain was woefully unprepared for the eventually outbreak of hostilities between the great powers in 1737 when it entered on the side of France and the Holy Roman Empire against Britain. Already weakened by infighting and the death of his second child, Charles III would die of stress in 1739, succeeded by his eldest son as Charles IV.