Lucian 
The True History 

According to Wikipedia: ‘True History or True Story is a travel tale by the Greek-speaking Syrian author Lucian of Samosata, the earliest known fiction about travelling to outer space, alien life-forms and interplanetary warfare. Written in the 2nd century, the novel has been referred to as ‘the first known text that could be called science fiction’. The work was intended by Lucian as a satire against contemporary and ancient sources, which quote fantastic and mythical events as truth.’