Alcalá de Henares, meaning Citadel on the river Henares, in Arabic قلعة النار, is a Spanish city located 35km northeast of the country's capital, Madrid. It stands out for its rich archaeology and was one of the first bishoprics founded in Spain. Locally, it is generally known simply as "Alcalá", but "de Henares" is appended when needed to differentiate it from a dozen Spanish cities sharing the name Alcalá (from the Arabic word al-qal'a القلعة for fortification or citadel). The Latin name, Complutum, is sometimes used. The city is the capital of its namesake region, Comarca de Alcalá. Its historical centre is one of UNESCO's World Heritage Sites.HistoryThe city boundaries have been inhabited since the Chalcolithic phase of the Bronze Age. Romans conquered the area in the 1st century BC, and built the town of Complutum near a previous Carpetanian settlement, called Iplacea. Thus, it became the only Roman town in the Madrid region. With 10,000 inhabitants, it reached the status of Municipium and had its own governing institutions. After the downfall of the Roman Empire, under the Visigoths, it declined, although it also became a pilgrimage destination in remembrance of the Saints Justo and Pastor.