Blood of Heros by Steve White
A well researched time travel tale. The author lays out the rules for time travel in his future universe up front, which is a plus in time travel stories. Our heroes travel back to bronze age Greece to observe a historical event and then the fun starts. They run into humanoid aliens. Very long lived, technologically advanced aliens. These aliens didn’t reproduce very often, but they had been there long enough produce a second generation. The older ones had names that included Chronos and Theia. The younger ones included Zeus, Hera, and Apollo. You can see were this is going. There is much action and adventure (adventure: bad things happening to other people far away). A fun read with two sequels already.