The Influence of Mongol Rule
All the devastating hordes of Genghis Khan's army played their negative role in the life of the Fergana Valley and Eastern ("Kyrgyz") Pre-Fergana. The number of cities and settlements significantly decreased after their invasion in the early 13th century. If Arabic-speaking authors of the 9th to 12th centuries counted 40 Fergana cities (including Osh) and large settlements with congregational mosques, then by the 15th century, sources mention fewer than ten cities. Productive forces fell into decline. However, regarding Osh, it seems that the city was not completely destroyed, as information about it still occasionally appears in sources. Nevertheless, the history of Osh during the time of Mongol rule in Fergana is almost unknown. Only isolated, fragmented, and charred pages of the city's history have survived to us through the flames of the centuries.
From the second half of the 13th century, Osh and its surroundings were part of the eastern part of the possessions of the Chagatai ulus, and then belonged to its dynasty for about two centuries. Mints in Osh and Uzgen operated episodically both during the Chagataids (the coin from 687 AH — 1288 AD of Osh minting is known) and during the rule of Timur and the Timurids. Archaeological finds from the 13th century in Osh are extremely few. The primary information concerns the burials of Muslim "saints." As can be seen from the epitaphs on the gravestones, the natives of Osh in the Middle Ages bore the nisba — the nickname "al Ushi" ("al Oshi") — "from Osh." This is one of the echoes of the once significant importance of the city of Osh.
The Iranian poet of the mid-14th century, Shams ad-Din Fakhr Isfahani, in his explanatory dictionary "Mayyori-i Jamali" ("The Beautiful Standard"), classifies the city of Osh as a settlement ("Ush — a settlement..."), which is direct evidence of the decline of urban life in Osh after the Mongol-Tatar invasion.