Simplify the following text for a Grade 9 native English-speaking person.
Original: The younger and healthier nobles and their families were marched north from TÃ cents rgoviÈ te to the ruins of Poienari Castle in the mountains above the ArgeÈ River , 40 miles north of TÃ cents rgoviÈ te .
Simplified: The younger nobles and their families were marched north from TÃ cents rgoviÅ te to the ruins of Poienari Castle in the mountains above the ArgeÅ River .