Conversation so far:
what did Matthew Paris do as a historian?
Paris continued the history on the plan which his predecessors had followed.
what was the history that the predecessors had followed?
He derived much of his information from the letters of important people.
what did he write about?
from conversation with the eyewitnesses of events.
did he write about anybody important in history?
Richard, Earl of Cornwall and King Henry III.
Did he receive letters from the people he wrote about?
He derived much of his information from the letters of important people.
Did he ever write about historical events?
Naturalists have praised his descriptions of the English wildlife of his time.
Did he write about any other events or was it just the one?
In 1257, in the course of a week's visit to St Albans, Henry kept the chronicler beside him night and day.

Question: who was Henry?
Self-contained rewrite: Who was Henry from 1257?