But it is to commerce that this capital is chiefly indebted for its splendour. By its situation, it is the entrepôt of that which is carried on between Russia and China. It is known that an intercourse is kept up by land; sometimes active, sometimes languishing; frequently interrupted, it has undergone so many variations, that it is necessary, in my opinion, to go back to the origin of this connection to judge of its consistence, and the improvements of which it is capable. The first accounts are dated in the middle of the last century, about the time of the invasion of the Mantchew Tartars, who, having for a long time ravaged the northern provinces of the Chinese empire, at last subjugated it entirely. It was to a governor of Tobolsk, that Russia was indebted for the first idea of effecting this commerce, in consequence of an attempt made at Pekin by persons of confidence whom he sent thither. Far from being discouraged by the trifling success of these emissaries, Russian and Siberian merchants united together to profit, if it were possible, by their discoveries. They sent out a caravan in the year 1670, which brought back new lights upon the subject, and unequivocal proofs of the possibility of succeeding. From that time companies multiplied, the journeys became more frequent, and establishments increased. This progress alarmed the Chinese, who resolved to set bounds to it. Forts were erected to restrain a neighbour, who, advancing nearer every day, by the river Amour, the Eastern Sea, and the Selinga, insensibly approached the frontiers of China. These defensive measures were the source of very warm disputes between the two empires upon the subject of their respective boundaries; a few hostilities took place, and at last an open rupture. Many years were spent in besieging places, in demolishing and erecting them in turns, till the year 1689, when the two courts, by the mediation of father Gerbillon and father Pereira, Jesuits, authorised by the emperor of China, signed, at Nertschinsk, a treaty of peace and perpetual alliance[102], which was to be engraven on two stones or posts erected on the confines of each empire. By this reciprocity, there was a free commerce secured to all the subjects of the two powers, who were furnished with passports by their courts. Meanwhile China had taken care to be paid for her condescension by the surrenders she demanded of Russia, who lost not only an important part of its possessions, but the navigation of the river Amour as far as the Eastern Sea.