Aztec records set the founding date of their city at 1325, when a band of nomads from the north settled on an island in Lake Texcoco. The city, called Tenochtitlán, eventually expanded to a population of more than 250,000, and by the 16th century it had become the seat of the Aztec Empire. The Spanish explorer Hernán Cortés first viewed the city in 1519. In 1521 his forces occupied and systematically levelled the great Aztec metropolis, building their own capital on the ruins. Lake Texcoco was filled in as the city expanded and was rebuilt in the Spanish architectural mode. From this new town, Spanish excursions explored and subdued the Native American inhabitants as far north as the present United States and south into Central America. Mexico City became the capital of all the Spanish provinces in the western hemisphere north of Costa Rica. It was administered by Spain for three centuries before being won in 1821 by a revolutionary band led by Augustín de Iturbide, later named emperor. During the Mexican-American War, Mexico City was captured by US forces in 1847 and held for five months. It was ruled by Emperor Maximilian and the French army from 1863 to 1867, when it was taken by President Benito Pablo Juárez. During the years of revolution following 1910, the capital was the scene of street fighting. By the 1920s, plans for the urbanization of Mexico City had been initiated. Industrialization increased as mills and factories spread throughout the city. Slum-clearance and housing-development programmes were initiated. Between 1930 and 1950, the population more than doubled. In 1985 a devastating earthquake caused severe damage, leaving nearly 30,000 homeless and thousands more dead.