After Nerchinsk regular caravans started running from Nerchinsk south to Peking. Some of the traders were Central Asians. The round trip took from ten to twelve months. The trade was apparently profitable to the Russians but less so to the Chinese. The Chinese were also disenchanted by the drunken brawls of the traders. In 1690 the Qing defeated the Oirats at the Great Wall and gained complete control over the Khalka Mongols in Inner Mongolia. In 1696 the Oirats were defeated and driven back to the Altai Mountains (Kangxi Emperor in person with 80,000 troops in a battle near Ulan Bator). This opened the possibility of trade from Baikal southeastward and raised the problem of the northern border of Outer Mongolia. In March 1692 Eberhard Isbrand Ides, a Dane in the Russian service, was sent from Nerchinsk as ambassador. The Manchus raised the question of the border west of the Argun. Ides returned to Moscow January 1695. From this time it was decided that the China trade would be a state monopoly. Four state caravans travelled from Moscow to Peking between 1697 and 1702. The fourth returned via Selenginsk (near Lake Baikal) in 90 days and bore a letter from the Li-Fan Yuan suggesting that future trade use this route.