https://www.logos.com/product/135823/encyclopedia-of-ancient-christianity
It's on sale. And it's one of those great resources that hide in the Orthodox bundles waiting for discovery.
From my count, Logos offers over 100 encyclopedias, plus dictionaries too, so there's quite a bit of overlap.
This (I think) fills a hole I'd wanted to resolve for years ... early development of all the different beliefs. And if you have the Fathers, it's very good in tracing from one to the next, contrasting, and discussing.
Of course, it has more ... early locations, people and issues.
There's others that also discuss, but not the careful tracing. It's closest match is one of the 2nd Temple dictionaries, in similar tracing.
It's major failing is rabbit-hole temptation-ing. It's very easy to go down several layers of a rabbit hole, and forget what you were reading.
It's on sale. And in the Factbook Collection too.
