Simplify the following text for a Grade 8 native English-speaking person.
Original: Throughout this time , at least as of 1919 , he was also President of the Irish Republican Brotherhood , and , therefore , under the bylaws of the Brotherhood , President of the Irish Republic .
Simplified: Throughout this time , at least as of 1919 , he was also President of the Irish Republican Brotherhood . Under the rules of the Brotherhood this meant that he was President of the Irish Republic .