Why did Egyptian Christians reject the decisions of the Council of Chalcedon?

Egyptian Christians rejected the decisions of the Council of Chalcedon (451) for both dogmatic and political reasons.1

Theologically, the council issued a formula affirming that Jesus Christ possessed two distinct natures—human and divine—that were neither commingled nor divided. Egyptian Christians, following the teachings of St. Cyril of Alexandria, viewed this "two-nature" (dyophysite) doctrine as a compromise of the belief in the divine Son. Instead, they upheld Cyril’s formula of "one incarnate nature of the Word," a position later known as [miaphysitism]. They maintained that Christ’s humanity and divinity were equally present in a single person, rejecting the accusation that they were monophysites who denied Christ's humanity.231

Politically, the council deposed Dioscorus, the Alexandrian pope, which alienated the Egyptian church from the imperial center in Constantinople. This rejection of Chalcedon allowed the Egyptian church to develop as a dissident institution, becoming a focus of indigenous identity and resistance against Byzantine rule.1