Old Mosque in Mértola
. Converted into a church
According to the Instituto Nacional de Estatística (the National Statistical Institute of Portugal), there were, according to the 1991 census, 9,134 Muslims in Portugal, about 0.1% of the total population, even though the Islamic Community of Lisbon presently points to a number of about 40,000. Most of the Muslim population originates from the former Portuguese overseas provinces of Guinea-Bissau and Mozambique, most of the latter having their origin in the Indian subcontinent.
From 711 to 1249, much of the territory of what is now Portugal (namely south of the Douro or Mondego rivers, but particularly in the Alentejo and the Algarve) was under Muslim control, and was called Al-Gharb Al-Andalus (the west of Al-Andalus). This presence has left a significant cultural heritage in Portugal, notably in the form of Islamic art. The Portuguese language has also been influenced, with many words borrowed from the Arabic language. The town of Mértola, in the Alentejo, possesses the only partial remains of a mosque. It had been converted to a Catholic church after the Reconquista.