Simplify the following text for a Grade 12 native English-speaking person.
Original: The Grand Duchy of Tuscany ( Italian : Granducato di Toscana , Latin : Magnus Ducatus Etruriae ) was a central Italian monarchy that existed , with interruptions , from 1569 to 1859 , replacing the Duchy of Florence .
Simplified: The Grand Duchy of Tuscany was a central Italian monarchy that existed , with interruptions , from 1569 to 1859 , replacing the Duchy of Florence .