Simplify the following text for a Grade 13 native English-speaking person.
Original: In Egypt , members of the Greek Orthodox Patriarchate were also known as Melkite , because they remained in communion with the Ecumenical Patriarch of Constantinople after the schism that followed the Council of Chalcedon in 451 .
Simplified: Members of the church were once known as Melkites , because they remained in communion with the Ecumenical Patriarchate of Constantinople after the schism that followed the Council of Chalcedon in 451 .