It was on 31 Aug 1422 that Henry VI became king of England at the age of nine months.
He was King Henry V's only child. In 1423, the year after he ascended to the throne, English nobles from around the land swore loyalty to their toddler king. They also set up a regency council to make government decisions until he was old enough to do so.
It was about a century and a half later that William Shakespeare wrote a historical trilogy of plays about Henry VI. To get information about King Henry's life and times, Shakespeare used a reference book called The Union of the Two Noble and Illustre Families of Lancaster and York, written by Edward Hall and published in 1548. The three Henry VI plays were among Shakespeare's earliest plays, and they were huge box office successes, helping to establish him as a major living playwright.
https://www.bbc.co.uk/history/historic_figures/henry_vi_king.shtml