Editorial contextTravelling from Nerchinsk toward the Argun, Ides saw hundreds of old, half-fallen castles of rough stone scattered through the valleys. His Tungus guides said warriors built them long ago, when Mongols and 'Western Tartars' raided the old kingdom of Nieucheu (the Jurchen or Manchu country). Iron-bound wagon wheels and millstones had also been dug up, which Ides took as a sign that a settled people once farmed and worked there.
In several scattered places in the Valleys, I observed hundreds of old, and partly fallen Castles, built with Rock-stones, which, as the Tunguzians told me, were built by several Warriours long since, when the Mongalian and Western Tartars made joint incursions into this Kingdom of Nieucheu. … And it is not long since that Waggon Wheels bound with Iron, and large Milstones were found in this Country
About Tungus informants; Mongol and 'Western Tartar' raiders
Keep in mind
Ides saw the ruins himself, but the story of who built them comes from his Tungus guides, and the idea that the Nieucheu people once lived there is his own guess.
Editorial contextDiscussing old silver mines on the Argun, Strahlenberg quotes the Dutch envoy Isbrand Ides that the Jurchens and Mongols once mined silver there. He then identifies the 'large and ancient city' of Alackzin in Abulghazi's Tartar history with the ruined city of Taiminzin that Ides described, once the seat of 'Chan Utay'.
But that large and ancient City, which this Tartarian Author calls Alackzin, is the now ruin'd City of Taiminzin; … See the Description which Isbrand Ides gives of the ancient City of Taiminzin, (p. 75.) formerly the Residence of Chan Utay:
Philipp Johann von Strahlenberg, author's footnote (English translation, 1738)