In Snorri Sturlason's "Heimskringla", a the history of the Norse kings, there is mentioned something called a "plate brynie". This reference comes from a story that is set between 1157 and 1161 A.D. Now a brynie is of course what we commonly call a chainmail shirt or mail shirt. So what is a plate-brynie?
From archaeological evidence, there are only two examples that come close in my mind. Both are from Sweden
The first is a grave find from Valsgarde which dates to the Vendel Age (550-793 A.D.): it appears to be a combination of ring-mail and splitted strips of iron that look like they would have been attached to leather straps with rivets.
Multiple pieces of armor found at site of the Battle of Visby (1391 A.D.) are made up of multiple plates riveted together that bears a resemblance to Eastern lamellar armor.
So for something that fits into the Viking Age (800-1000 A.D.), I came up with this: the plates are linked together with rings and incorporated into the mail shirt as essentially the front of the armor. While not based on anything specifically historic, I feel that it would be a logical development in armor going from the classic mail shirt to the plate armor that was found in Visby.
