The higher is the value, the slower it moves.
So...horseman is the fastest from your given examples.

Quote clanas:

I've checked the speed values of the different units.

A swordsman's speed is 360 in valley and 27 in city. A knight's speed is 280/21. A horseman, which is a lighter unit than knight...is even slower: 240/18.

How can it be that everything is upside down? That swordsman really knows how to sprint, right? Or higher speed value = slower unit..? :O

You're absolutely right,

the speed values in 1100 A.D. seem counterintuitive based on our real-world understanding. Here are two possibilities:

1. Inverted Speed System: It's possible that 1100 A.D. uses an inverted speed system. In this case, a higher number might actually represent a slower unit. This might be done for technical reasons or for a specific gameplay mechanic.

2. Hidden Speed Factors: The displayed speed values might not be the whole picture. There could be hidden factors affecting movement speed, such as terrain type, unit weight, or fatigue. For example, a swordsman might be faster in open terrain (valley) due to lighter equipment but slower in cities due to crowded streets and obstacles.