Stirrups is a technology in Age of Empires II: Definitive Edition that is unique to the Bulgarians and can be researched at the Castle. Once researched, it increases the attack speed of the Scout Cavalry line and Konniks by .
Note that Dismounted Konniks are unaffected by Stirrups.
Mounted Konniks have the slowest melee attack in the game; however, after researching it, their attack rate drops to that of a Knight (1.8), while having a higher base attack than Knights, so in the Castle Age, this technology is a must research if the player wants to utilize them, though it is quite expensive and Blacksmith technologies should still be prioritized first. In the post-Imperial Age, Elite Konniks attack faster than Paladins. This, combined with their easy creation and and being able to fight dismounted, make the Konnik one of the best cavalry units in the game, as well one of the finest unique units.
Stirrups also affects light cavalry, which puts their Hussars at a huge advantage in "trash wars", and probably makes a fully upgraded Bulgarian Hussar the strongest in the game and able to defeat in one-to-one combat generic Hussars, Mongol Hussars, and even Malian light cavalry with Farimba.