Conversation so far:
How did Matthew Paris become a historian?
From 1235, Matthew Paris continued the history on the plan which his predecessors had followed.
What was the plan Matthew Paris' predecessors has followed?
Roger of Wendover's best-known chronicle, called the Flores Historiarum (Flowers of History), is based in large part on material which already existed at St Albans.
Was being a historian related to church for Matthew Paris?
The Flores Historiarum is the name of two different Latin chronicles by medieval English historians that were created in the 13th century, associated originally with the Abbey of St Albans.

Question: what did he do in 1257
Self-contained rewrite: What did Matthew Paris do in 1257?