I've caught the tail end of a great lecture by a priest but have not been able to identify him or the venue. What I recall clearly is the very interesting point he brought up about the importance in understanding the mystery cults (Dionysus, Tammuz, Mithra, ect) which were the competing faiths at the time. The priest seemed to be speaking to the point of how Paul used his knowledge of these mystery cults to "speak the language" of the peoples and regions he sought to evangelize.
I followed the logic of the larger arc of that narrative, in that, Christianity was a fulfillment or solution to all these legacy faiths. The priest conceded that it wasn't a perfect overlap; Paul would cherry pick certain aspects from the mystery cults to serve as a vehicle for his message. Clearly, a blanket comparison would be incompatible. Tammuz is Tammuz, one would have to let go of the notion that Tammuz governs ones crops. But perhaps the priest meant certain subsets of ideas within these cults were able to be re-purposed.
QuestionWhat kind of mystery cult ideas did Paul appear to focus on when evangelizing Rome and/or the Near East?
Note: Will leave the answer open to any/all sources, scripture, letters or other.