The Hittites were one of the largest empires in the ancient world, but up until the last two centuries, the only proper documentation of them was in the Bible, which is why many historians suspected that they were a fictional civilization.
In 1834, French archaelogist Texier found the ruins of their capital Hattusa in modern day Turkey. But he assumed it was Pteria, a city mentioned in ancient Greek documents.
It took another ~ 70 years for German archaelogist Winckler to realize that this was the Hittite capital, based on clay tablets.
The Bible is not proper documentation of the Hittites. All the texts that mention the Hittites post-date the fall of the empire based out of Ḫattuša by centuries. It's an open question whether the Hittites of the Bible refer to Ḫattuša or "Neo-Hittites" better described as Luwian-Aramean.