Cordoba was founded by the Romans and due to its strategic importance as the highest navigable point of the Guadalquivir River, it became a port city of great importance, used for shipping Spanish olive oil, wine and wheat back to Ancient Rome. The Romans built the mighty bridge crossing the river, now called "El Puente Romano". But Cordoba's hour of greatest glory was when it became the capital of the Moorish kingdom of El-Andalus, and this was when work began on the Great Mosque, or "Mezquita", which – after several centuries of additions and enlargements – became one of the largest in all of Islam.