How do conversions with multiple monks selected work?

I had to look this up because I was curious about this myself.

From the fan wiki on Age of Empires about Conversion (https://ageofempires.fandom.com/wiki/Conversion):

From The Conquerors onwards, AI Monks attempt to convert their target at regular intervals, called here conversion intervals (CI), roughly equal to 1 game-time second. Once a Monk is at conversion range of his target (or touches it in case of rams, Trebuchets, and buildings), his first CI starts. His three first CIs have no effect on the target and only serve as warm-up. Starting from the fourth CI, the Monk has a 28% chance to convert a unit at the end of every CI. The Monk is guaranteed to convert his target at the end of the 10th CI. Attempts to convert buildings start at the 15th CI and are guaranteed to succeed at the end of the 25th CI.

What this means is that having more monks convert an enemy target helps a bit in that you have more "Conversion Intervals" that might trigger the conversion itself. However, because all monks are attempting to convert the target, they are all considered to have converted the target.

There's a very interesting post on Reddit that covers this in a lot more detail: https://www.reddit.com/r/aoe2/comments/4aj2c0/how_monks_really_work/