Your Title is tied to your level in the game. 
 All players start at Level 1 as a Lord as their Title. 

To raise your level you need to acquire an amount of might. 
Depending on the new level your Title may change as well.

Your might will go up when you increase Troops, and it will go down when you lose them. 
Your level, and your title will never go down. 
Once you acquire enough might to advance your level, that level will not drop even if your might goes down.