Every once in a great while you stumble across a great resource, in this case, I found two of the best.
The British Library and The British Museum
Between these two they offer probably the most extensive online catalogs you can access without a subscription.
The British Library offers full-text views of manuscripts. The British Museum has a wide and searchable catalog.
Some of the highlights
Anglo-Saxon Exhibit – As someone whos persona focuses in this time this exhibit is a dream come true. While a fair number of the items are not accessible online the twitter feed has been amazing at giving a glimpse.
The Manuscripts– This is the heart of the catalog. Start here to find a wealth of illuminations.
8th Century Manuscript– This is probably one of the earliest intact manuscripts. Well worth a look
The British Museum offers extensive photos of its vast collection. You can also find more at Google Arts and Culture who also has some of the highlighted items of the collection.
I had a good time looking in the Anglo Saxon items! This Ring was a pleasant surprise I had been given a ring similar to it.
