The Eternal Truth of the Holy Trinity, the true nature of God has been explicitly declared by the Apostolic Churches and Holy Scripture. It has been reinforced by the Churches and is reinforced every time we make the sign of the cross. But when was it first declared?
It was declared in a person first. Her existence will always declare it without a word uttered about it. It will always be declared by her image, also without a word said. Because when the Angel declared the virginal conception of her Son in her, a creature of God the Father became the Mother of God the Son who had to have been conceived in her by God the Holy Spirit. Her image will always declare the Holy Trinity, without a word said.