First SciFi novel ever: A 2nd century AD book about traveling to outer space, meeting aliens and Homer

Some argue that the first genuine science fiction novel is Mary Shelley's Frankenstein, where technology bordering necromancy is used to reanimate the dead. But labeling what falls under science fiction can be troublesome. Christopher McKitterick says that in the strict etymological sense, it's literature about scientific discovery or technological change, but then argues that this definition misses the mark; instead Mckiterrick believes "SF is about how we have changed, how external change affects us, how things we do change the world around us, and how we will continue to change over time." What about works of fiction written in a time when science wasn't even considered a distinct field, separate from natural philosophy, or study of religious truth, etc? Depending on how you class what makes science fiction, Lucian of Samosata's "True Stories" might be the first science fiction novel. The characters venture to distant realms including the moon, the sun, and strange planets and islands. The star protagonist is Lucian himself who happens to stumble upon aliens on the moon and finds himself in the midst of a war between the lunar and sun empires.