This period was the first major internal crisis in Moscovian history. Merchants requested to regulate their matters on their own instead of local dukes. Bureaucrats wanted to take control of the day to day management of the Grand Duchy from local dukes. Duke of Uglish wanted to overthrough Ivan's control and reform his duchy to an indepedent city-state!
However, all (except duke of Uglish) stayed loyal to the Ivan, so he could manage the crisis successfully. Ivan accepted the merchants claims, but their powers are limited to their corresponding markets, while they have to stay loyal to their local dukes.
Bureaucrats cried that local dukes will make them inefficient, but they accepted Great Duke's decisions. Ivan intervered in Uglish and imprisoned the duke setting his duchy under military control. Literature lovers hated Ivan for this decision. They revenged him by calling him "terrible" in their works. A characterization that remained in history.
The crisis was over after some years.
The royal counsil was occupied with the crisis, so Ivan had to decide alone what scholars should discover next. He decided engineering might help against nomads.
The Caricynian army was completed in 1189AD. A shining example that all other duchies indluding Moscow should immitate.
Ivan upgraded all mounted units in the empire paying a large cost, but it worthed it.
An explosion occured near Uglish. It seems Uglishians didn't like what Ivan did to their duke, and he should pay the price.
In the year 1204 a gifted child was found in Moscow. He was the son of the librarian, who worked in the local forge. His ideas were interesting and scholars were amased by his wisedom.
Meanwhile the khganate of Kazan established control in the east. Ivan ordered the caricynian cavalry to conquer it.
Unfortunately, Kazanians were stronger than expected. One third of Caricynian cavalry died.