I believe I've managed to debunk the "13th century" date on the manuscript I've been working with!

It all comes down to fine details.

The pricking for page ruling was only done on one side of the margins. That was a trait you rarely see between about 1150 and 1250, when it was the norm for margins to be pricked on both sides. But after about 1250, the Gothic hand had taken full hold and the distinctly Insular, angular Protogothic hand that this is written in is more consistent with an earlier date.

There is one colored capital that displays the red pen flourishes typical of later Gothic manuscripts of the 13th century, but the remainder of the non-illuminated capital letters do not have this feature. It is my opinion that this is the work of a later scribe.

Based on the evidence, I now believe this book was made in or near the first half of the 12th century. The slightly more Insular flourish on the miniscules suggests it was made in southeast England, but it could have been made in France just as easily during this period as the Protogothic style spread quickly throughout England and France.

Given that this was made so early, it is possible that this manuscript was copied from an original copy of Peter Lombard's text but I doubt it is THE original copy.

Pics to come, plus updated files for the earlier pics I posted.