Simplify the following text for a Grade 10 native English-speaking person.
Original: Kwanzaa is a celebration that has its roots in the black nationalist movement of the 1960s , and was established as a means to help African Americans reconnect with their African cultural and historical heritage by uniting in meditation and study of African traditions and Nguzu Saba , the `` seven principles of blackness '' which Karenga said `` is a communitarian African philosophy '' .
Simplified: Kwanzaa is a celebration that started in the black nationalist movement of the 1960s . It was created as a way to help African Americans reconnect with their African cultural and historical heritage .