Luís I was King of Portugal was 28 years in the second half of the 19th Century.

He was born on Oct. 16, 1838, at Necessidades Palace in Lisbon. His mother was the reigning monarch, Queen Maria II, and his father was Ferdinand of Saxe-Coburg and Gotha. Luís was his parents' secondborn son; their first, Pedro, succeeded his mother as monarch when she died in 1853. The former king consort and royal father served as regent for King Pedro V for two years until the latter came of age.

Pedro, as heir apparent, learned all the things needed to become a king. Luís, as the second son, learned all things navy and gained his first command in 1858, when he was 20: His brother named him commander of a newly commissioned warship, the Bartolomeu Dias. Part of that command was a tour of his country's African colonies. Another of Luís's missions was to bring Princess Stephanie of Hohenzollern-Sigmaringen to Portugal so she could marry Pedro V.

Pedro died of typhoid fever in 1861, and Luís succeeded him as king. Luís, like his older brother, was a passionate learner and a good student. He had the command of music, playing cello and piano, and of several languages; he also enjoyed painting and writing poetry. A student of literature, he was the first to arrange for Portuguese-language versions of the plays of William Shakespeare. He did not develop a taste for politics.

In 1862, Luís married Princess Maria Pia of Savoy, whose father was King Victor Emmanuel II of Italy. The royal couple had three children, two of whom survived into adulthood: Carlos (1863) and Afonso (1865). Maria Pia was known for her support of people of all economic classes, primarily the poor. She became known as "the angel of charity."

Firing his earlier naval studies was a deep love of oceanography. Luís funded a fleet of research ships to sail the world in search of specimens to display in the Aquátio Vasco da Gama, one of the world's first aquariums, which he had built in Lisbon.

The economy during Luís's reign was unstable, as was the political landscape. The country's two main political factions, the Conservatives and the Liberals, heightened their power struggle during this time. Pedro V had been such a beloved king, and Luís was in many ways not his brother; a military uprising in 1870, intended to replace Luís with the Duke of Saldanha, the prime minister, failed in the end, but only just.

Luís did have successes in other areas. The port of Lisbon developed during this time, and efforts to extend the railway and road networks were successful.

Luís died on Oct. 19, 1889, in Cascais. His death was sudden. His oldest son became King Carlos I.