About this time the Kangxi Emperor began to put pressure on Saint Petersburg to delineate the Mongolian border west of the Argun, and several Russian caravans were held up. In July 1719 Lev Izmailov was sent as ambassador to Peking where he dealt with Tulishen, but the Chinese would not deal with the trade problem until the border was dealt with. Izmailov returned to Moscow in January 1722. Lorents Lange was left as consul in Peking, but was expelled in July 1722. He returned to Selenginsk and sent reports to Petersburg.