This is a condensed version of an earlier post.
We have to start with Flavia’s connection to the Judean ethnic group, Princess Berenice.
In the 80s, Berenice, in exile in Rome, very likely attended the pre-Papal Roman congregation. It was the best alternative to Pharisaical synagogues. (My suggestion is plausible because the Papal Roman congregation preserved the memory of a BeReNiKa connection under the name of Roman “saint” VeRoNiKa.)
Berenice, I believe, mentored Flavia Domitilla. (In the 80s-90s, Flavia was a young mother of seven children, who needed mentoring.)
Flavia was not a member of the Roman congregation
Flavia could not have been a member of the Roman congregation. In the early 90s, she and her husband Titus Flavius Clemens were the parents of two boys that Domitian had marked out as his successors. Her first responsibility was to propriety. The congregation was composed of civilized, Hellenized people—but people of an ethnos that had just been defeated in war by the Flavian family.
Berenice, on the other hand, was affiliated with the congregation
The Herodian princess Berenice needed a place to socialize with well-to-do, Hellenized Judeans. (She could not socialize with Pharisees because as a client of the Flavians, she dined with them and therefore transgressed Pharisaic purity rules.)
Was Berenice a member, an associate, or an occasional attendee? There’s no evidence for any. But it makes sense that Berenice, who was over 50 and who had no peers in Rome, wanted to expand her social circle. I think it’s safe to say she was affiliated with Mark’s congregation. (Which, after all, later remembered her as “Veronica.”)
Berenice linked Flavia with the congregation
It seems to me likely that Berenice told Flavia about the Roman congregation, and Flavia expressed curiosity. Perhaps Flavia attended some event at the congregation. In any case, she knew it was important to Berenice, and Berenice was her mentor.
Berenice needed a place to be buried
Berenice needed a place to be buried. In the 80s, she was over 50. She could not be buried far away in Judea. She could not be buried in Pharisaic ground in or near Rome. She could not be buried in Gentile ground. She was a princess, and a client of the Flavian family. A dedicated piece of Flavian family ground would seem to be the logical solution.
Flavia gave the congregation the use of catacombs so Berenice could be buried there
I suggest that Berenice originally planned to be buried in the ground/catacombs that was already used by Mark’s congregants. But Flavia came to the rescue. I suggest that Flavia offered her mentor Berenice a special section in Flavia’s family catacombs, on Flavia’s property.
And (probably after Berenice’s death) Flavia extended that offer to Mark’s congregation, in general. And it was to accompany that announcement that Flavia produced a play, and celebrated with a grand dinner.
The offer was extended to Mark’s congregants
Why would Flavia extend that offer to Mark’s congregants, in general?
First, at the time the congregation must have been small, with no apparent prospect of becoming large, much less the headquarters of a church. Second, if the event occurred at or just before her husband Clemens’s consulship (in early 95), the offer could be seen as a political gesture of benificence to a well-to-do and well-behaved constituency. Third, Flavia would have assumed that with seven children, and future emperors among them, her family catacombs would be in use by Flavians for many decades. She did not know that within the next decade Domitian would wipe out her family, and the Flavians would disappear from history!
So Flavia couldn’t have imagined the long-term advantage her donation of real estate would give to the Roman congregation. After the death of her family, they had access to—and perhaps, control of–a tangible benefit they could offer to prospective members.