count of Provence (1347–62), as well as prince of Taranto and Achaia, who by his marriage to Queen Joan I of Naples (1343–82) became king of Naples after a struggle with King Louis I of Hungary.

Louis, who is believed to have played a major role in the murder of Andrew of Hungary, Joan's first husband (September 1345), married Joan in August 1347. When Andrew's brother Louis I of Hungary invaded the kingdom, occupying Naples (1348), the royal couple fled to Avignon, where they received the protection of Pope Clement VI. The Hungarian king left Naples, which Joan and Louis reoccupied briefly before a second Hungarian invasion forced them to flee to Gaeta. Louis' final departure allowed them to return for good in 1352. In the presence of the grand seneschal Niccolò Acciaiuoli (1310–65), their major supporter and counsellor, they were crowned in Naples by a papal legate.

Having usurped the royal power from Joan, Louis regained much of the island of Sicily, including the capital of Palermo. A barons' revolt, however, forced him to return to the mainland, where he defeated his enemies. His sudden death prevented his return to Sicily.

king of Portugal whose reign (1861–89), in contrast to the first half of the century, saw the smooth operation of the constitutional system, the completion of the railway network, the adoption of economic and political reforms, and the modernization of many aspects of Portuguese life.

The second son of Queen Maria II and her consort, Ferdinand II, Louis succeeded on the early death of his more brilliant elder brother, Peter V. He married Maria Pia, daughter of the King of Italy, in 1862. The reign began inauspiciously amidst financial difficulties.

In 1868 the question of the Spanish succession caused a crisis when Napoleon III favoured the succession of King Louis or his father Ferdinand. Louis weakly allowed Marshal Saldanha to seize power, but the aged hero was soon forced to resign. Unlike his predecessor, Louis preferred the conservative Regenerator Party, which, under the minister António Maria de Fontes Pereira de Melo, pursued a policy of economic development and deficit financing. The Progressists accused the King of partisanship and thus favoured the emergence of republicanism. King Louis took a hand in treaties with Britain concerning Mozambique and India and helped to settle other territorial disputes through arbitration. He translated Shakespeare and other works into Portuguese.

king of Spain in 1724, son of Philip V.

Louis was born during the War of the Spanish Succession, which disputed his French father's succession to the Spanish throne; thus, his birth was celebrated by the French and the Spanish. Louis XIV of France was his great-grandfather. In 1709 he was recognized as heir presumptive, being named príncipe (prince) de Asturias, and succeeded to the throne on Jan. 15, 1724, upon the abdication of his father. On February 9 he was formally proclaimed king. He fell ill, however, probably of smallpox, on August 19 and died 12 days later. Philip V returned to the throne.