Simplify the following text for a Grade 13 native English-speaking person.
Original: The Principality of Khachen , also known as Khamsa ( meaning five in Arabic ) , was a medieval Armenian principality in the territory of historical Artsakh ( present-day Nagorno-Karabakh ) .
Simplified: The Principality of Khachen was a medieval Armenian principality , in part of historical Artsakh ( present-day Nagorno-Karabakh ) .