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
Mongolia–Russia border Mongolia–Russia border The Mongolia–Russia border (, "Mongol-Orosın xil"; , "Rossijsko-mongoljskaja granica") is the international border between the Russian Federation (CIS member) and Mongolia. It is virtually all land. The total length of the border is 3485 km. The boundary is the third longest border between Russia and another country, behind the Kazakhstan-Russia border and the China-Russia border. The Russian state expanded into the regions north of today's Mongolia in the 17th century. Much of the line of the today's Mongolia–Russia border line was set by the Treaty of Kyakhta (1727) between the Russian and Qing Empires (the Mongolia at the