Karakorum destroyed, then so forgotten no one knew where it was
Editorial contextAfter the Mongol emperors were driven out of China, Ritter says, Karakorum briefly became their capital again and a base for raids on China, until it was destroyed in the wars between the Oirats and the northern Mongols, which he places around 1415. After that the records fall silent so completely that even its location was forgotten, until the French sinologist Abel-Remusat fixed it again from Chinese texts; Ritter wishes physicists and antiquaries would go and examine the site. On the same page he summarises William of Rubruck's description of the khan's brick-walled enclosure, palace and the foreigners from every nation living there.
Karakorum served them only for a short time as a stronghold from which to attack the Chinese frontier; for in the wars of the Oirats and the northern Mongols it was destroyed … All later reports cease so completely at this point that even the location of the place was forgotten, until Abel-Remusat's critical research could once again assign it its proper position.
Working translation
Original wording
Es diente ihnen auch Karakorum nur kurze Zeit als Waffenplatz, um von da aus die Chinesischen Grenzen anzugreifen; denn in den Kriegen der Oirad und nordischen Mongolen wurde es zerstört, … Alle spätern Nachrichten hören hiermit so ganz auf, daß selbst die Lage des Ortes vergessen war, bis Ab. Remusats Critik demselben von neuem seine richtige Stelle anweisen konnte.
About Mongols and Oirats (western Mongols)
Keep in mind
The date of about 1415 is Ritter's own inference from a Mongol chronicle's mention of rebuilding the city.