[rkangel]

Git as a system has no objection to having more than one 'initial commit'. It will happily take that branching history and merge it together. With a bit of branch renaming you can add extra remotes to your repo so both 'masters' are present. Commit to both to make the resulting directory structure not overlap, and then just merge. You'll end up with full history of both.

I did a quick google and these instructions seem about right (without the delete step): https://gist.github.com/msrose/2feacb303035d11d2d05