History of Portugal (1640–1777) put to the test in 1762 when Spain invaded aided by France, during the Seven Years' War. Britain invoked its alliance with Portugal and sent troops. Several months later, the conflict was settled with comparatively little fighting. In 1777, Spain and Portugal signed the Treaty of San Ildefonso, which mainly resolved a number of border disputes between their South American colonies. During the Age of Enlightenment, Portugal was considered one of Europe's unenlightened backwaters; it was a country of three million with 200,000 people in 538 monasteries in 1750. Melo seems to have been deeply embarrassed by Portugal's much lamented
Portugal all over modern Portugal and remains of Castro culture. Numerous Roman sites are scattered around present-day Portugal, some urban remains are quite large, like Conímbriga and Mirobriga. The former, beyond being one of the largest Roman settlements in Portugal, is also classified as a National Monument. Conímbriga lies from Coimbra which by its turn was the ancient "Aeminium"). The site also has a museum that displays objects found by archaeologists during their excavations. Several works of engineering, such as baths, temples, bridges, roads, circus, theatres and layman's homes are preserved throughout the country. Coins, some of which coined in Lusitanian