It is unfortunate that a most widely extending overview, delivered by a historian is no longer available on the web: MMW3 from UCSD. Why UCSD removes their podcasted lectures immediately after the closing of the course is beyond me. Maybe they think only their students are to be served, but in that respect they are alone in the world of academic podcasts. Other institutions offer a formidable backlog for us to browse from.
As to early Christianity, the content is largely delivered by theologians. The first era to discuss would be the life of Jesus, or Yeshua, himself. This is covered in The Historical Jesus, by Thomas Sheehan from Stanford (feed). Not only is this an excellent series, you can also access a lot of the source material on-line, free of charge.
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The widest range I know of is Covenant Seminar's Church History, which kicks off with the early apostolic period, quickly moves on to the early church years and eventually ending before the Reformation. In this series the theology, doesn't necessarily overshadow the history, but the narrative and lecture carries very noticeably the Presbyterian signature of the producer.
Relevant other reviews:
Church History,
World history guided by the religions,
The Nicene Creed - IOT,
Historical Jesus - Tom Sheehan, Stanford.
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