I almost forgot to put pictures of one of my favorite parts of Ostia-the Square of the Guilds/Corporations. This large square off of the theater was originally separated from the theater by a large wall. It started as a place for theater-goers to congregate, but over time took the current form. It was a large square surrounded by a portico. Under the portico, there were individual rooms. Each of these rooms were occupied by a guild or corporation engaged in a certain line of work. The cool thing is that the mosaic in from of each room depicted what the group did. Some have pictures, and some have pictures and words. They advertise wood cutters, shippers, traders in rome, traders in wild animals, etc. It was really interesting. In the middle is a small temple. The god to which this temple was dedicated is unknown, but it is assumed to be one related to commerce.
This is a view of the Square of the Guilds from the theater.This group presumably traded in exotic animals and/or ivory.
Here's a view down one of the sides. You can see the individual rooms and the advertisement in front of each.
This is one of the cool carved masks that decorated the theater.