This question could be rephrased as:"How warm was the medieval warm period?"
Steve McIntyre was assigned this topic for a talk given at Ohio State University on Friday May 16,2008. When the talk was posted on the Climate Audit blog on May 22 it drew a very positive response including this comment:
retired geologist says:
May 22nd, 2008 at 11:45 am
What a wonderful summary of your OSU talk. Everyone who reads your blog should read every word of this talk. As a 1961 graduate of Ohio State’s Geology department I’m especially pleased and proud you gave your talk at OSU. After reading this I don’t see how anyone with even a single functioning brain cell could still have faith in any of the IPCC work. In the past I’ve directed some pretty harsh comments at Steve. I take them all back. Sorry.
The outline of the talk can be found here.