Historical fiction, such as Downton Abbey, is a literary genre using places, people, and events from the past to tell an original story. However, this type of writing wasn’t done at that time. The genre of fiction wouldn’t even exist for another 1,000 years.
No, Luke is specifically claiming that the reported events actually happened and goes into lengthy detail describing them. He writes in the form of a report to an authority figure. At the beginning of his Gospel (story of the life of Jesus), he says:
“Having carefully investigated everything from the beginning, I also have decided to write an accurate account for you, most honorable Theophilus, so you can be certain of the truth of everything you were taught.” –Luke 1:3-4