The higher your Nobility Rank, the more cities you will be able to control. To quickly upgrade your Nobility Rank, you can use certain items.

You can use either a "Medal of Honor I" or ' Medal of Honor II." 

"Medal of Honor I" will temporarily upgrade your Nobility Rank by one level.

"Medal of Honor II" will temporarily upgrade your Nobility Rank by three levels. 

The level could be increased three level maximum when use "Medal of honor" overlap.