The Armenian Church accepts the first three ecumenical councils summoned at Nicaea, Constantinople, and Ephesus. In the 5^th century the Armenian Church did not accept the Council of Chalcedon in 451. In 506 at the Dvin Council, the Armenian Church formulated an official response to Chalcedon defending its Christology.

The Armenian Church has its distinctive theological and liturgical features: it uses unmixed wine and unleavened bread. In terms of the feasts, the Armenian Church is the only Church today that celebrates the Christmas and Epiphany on the same day: January 6.

The Armenian Church has a rich liturgical tradition. The liturgy is patterned after the directives of Saint Gregory the Illuminator, first official head and patron saint of the Armenian Church.

The Armenian church architectural style is also quite unique.

Being faithful to its historical, theological, and liturgical traditon, the Armenian Church was also always open to mutual, respectful, and honest dialogue between different peoples.

Source.  www.sacredtradition.am