wow its been awhile since i posted but i kind of remember the answer to this question
in the main courtyard you go in one of the doors, and whichever one has the guards beds at the top is the one u want. you go in that door, and go the lowest the stairs will take you, and then go in the jail. inside there r 2 guards who u need to kill before u can unlock the chest, which is on some boxes in the corner.