Ancient Roman sculptures were something that people of higher rank or nobility enjoyed. Many of the original works of art have been lost, or destroyed by time. However, there are some that have been found, and restored. The subjects of ancient Roman sculptures primarily were people. Since ancient Rome was a pagan society, there were many sculptures to depict their gods. Many of these gods were Roman adaptations of Greek gods that were discovered after Rome conquered Greece. The names were changed, but the purpose of the gods remained the same.
Many ancient Roman sculptures were portraitures. They were bust of people such as family members, the ancestors, or political figures. These busts would be displayed for all to see in the drawing rooms and entrance areas of grand halls, and the homes of the nobles. There were also scenes of life that were depicted. There were scenes, such as the change of seasons, and how those seasons affected people in everyday life. There were sculptures of little kids playing, and of military formation. A sculpture of a military or a political figure was common, because these were seen as grand people.
It's interesting to note that unlike other art forms through the ages, those who commissioned a bust of themselves wanted to be portrayed exactly as they were in the moment. They didn't want any facial features or flaws covered up. It was considered noble character to show yourself off as you were. This type of thought flies in the face of many other types of art, especially in today's world of photoshop, and other forms of cover up.