Short answers, pulled from the story.
Charles IV of Spain was king from 1788 to 1808, ruling for two decades before abdicating twice in a single year. Born on the 11th of November 1748 in Naples, he was the second son of Charles III and Maria Amalia of Saxony.
Charles IV abdicated twice in 1808. He first abdicated on the 19th of March following the Tumult of Aranjuez, a popular revolt at the winter palace, in favor of his son Ferdinand VII. Then in April 1808, Napoleon Bonaparte summoned both father and son to Bayonne and forced Charles to abdicate a second time, deposing the Bourbon dynasty entirely and installing his brother Joseph Bonaparte as king.
Manuel de Godoy served as first minister under Charles IV and was the dominant force in Spanish policy during his reign. He was widely believed to be the lover of Queen Maria Luisa, and his economic policies and management of foreign alliances deepened public discontent with the monarchy. Godoy was ousted during the Tumult of Aranjuez in March 1808 alongside Charles's abdication.
Charles IV authorized or continued several major expeditions, including the Malaspina Expedition (1789-1794), led by naval commander Alejandro Malaspina, and the Balmis Expedition in 1803 to vaccinate Spain's overseas territories against smallpox. In 1799 he granted Alexander von Humboldt permission to travel freely throughout Spanish America, work that produced Humboldt's Political Essay on the Kingdom of New Spain.
Francisco Goya painted Charles IV in a number of official court portraits. Art critics have widely interpreted those portraits as satires on the king's stout vacuity rather than straightforward celebrations of royal power.
In 1804, Charles IV ordered the Catholic Church in the overseas empire to call in immediately the long-term mortgages it had extended to landowners. Wealthy elites in New Spain had no means to make full payment on their mortgaged properties and faced financial ruin. The decree has been identified as a significant factor in turning elite opinion toward the independence movement in New Spain, the territory that became Mexico.