The Moors, who were Muslims and ruled Spain for 800 years, introduced new scientific techniques to Europe, such as an astrolabe, a device for measuring the position of the stars and planets. Muslims founded the first Spanish university at Valencia in 1209. At its height, Córdoba, the heart of Moorish territory in Spain, was the most modern city in Europe, with streetlights and running water. The Moors were also advanced in medicine, science, and astronomy, and Arabic words such as algebra, alcohol, chemistry, nadir, alkaline, and cipher entered the language. The Moors occupied Spain for 800 years; consequently, over 4,000 Arabic words and Arabic-derived phrases have been absorbed into the Spanish language. Words beginning with “al,” for example, are derived from Arabic. The name “Madrid” is from the Arabic magerit, which means “place of many streams.”