According to a report in the Jordan Times newspaper, a very early underground church was found beneath the ancient Saint Georgeous Church, that itself dates back to 230 AD.
See:
- http://rihabresearchcenter.blogspot.com/
- Jenn Cianca, Lincoln Blumell: The Oratory of St. George in Rihab: The Oldest Extant Christian Building or Just Another Byzantine Church?, https://www.academia.edu/1399379