Quote Originally Posted by MJF
im not sure if this is correct but this is how ive always read it.

you cant build dismounted units in vanilla games but you can dismount the units in certain conditions i.e. sieges.
Correct. Many mounted units can dismount, depending on the situation. Some units can dismount in any type of battle, some can dismount only in sieges, and a few cannot dismount at all.

Quote Originally Posted by MJF
so if you produced a crusade in rhodes and obtained some hospitaller knights, if you storm a city, and during the siege battle you dismount the knight units, they will obtain a bonus valour.
As macsen rufus has said, this is incorrect. To reiterate:
Quote Originally Posted by macsen rufus
When dismounting units the valour doesn't change - a v0 mounted knight will dismount to a v0 foot knight even if it was trained in a v1 province for foot knights.