See the Wikipedia page for some basic inforamtion about the town of Torremaggiore where the castle was located. This old photo gives a good idea of what the castle woudl have looked like in its Renaissance version. The castle was actually located some distance away from town of Torremaggiore, which was founded in 1218 as a Byzantine border fortress.
It would be interesting to find out what archaelogists have discovered about what the castle was like in 1250. Now there is very little there apart from some ruined walls as you can see from these photos and here and the video below.
This is an interesting YouTube video that shows the ruins of the castle: