I saw some scenes from this on a TV with no sound, but it intrigued me. I don't think it was Gladiator or 300, although it looked a bit similar. To be honest, it could be a TV show, but I don't think so. It was rated TV-14.
There were these two armies fighting with ships, and they were ramming other ships with slaves rowing them. There was this one guy who was throwing lanterns at one ship and setting it on fire, and when this one guy fell into the water there were these giant snake-fish things that ate him, which makes me think that this might've been Roman fantasy.
The most distinct scene was about this girl. I think this was a flashback where these soldiers burned down her home and took her captive, then there's a cutaway scene where she was raped. The next scene is her lying bloody and bruised on the street, but a man picks her up and takes her to a place when he trains her in sword fighting. I think she's grown up then, and she has a throne on one of the ships and is leading her army.
Also, this guy was in the movie:
I didn't get any photos of the more notable scenes.