Simplify the following text for a Grade 6 native English-speaking person.
Original: The Irish Free State ( 1922 â `` 1937 ) was the state established as a Dominion on 6 December 1922 under the Anglo-Irish Treaty , signed by the British government and Irish representatives exactly twelve months beforehand .
Simplified: The Irish Free State was the name of the Republic of Ireland from 1922 to 1937 .