The 'lesser doxology' — the Church's ancient hymn of praise to the Holy Trinity; its trinitarian form pressed into universal use in the fourth century against the Arians, its closing clause a Western addition affirming the Son's eternal glory.
Glory be to the Father, and to the Son, and to the Holy Spirit; as it was in the beginning, is now, and ever shall be, world without end. Amen.
The dated sources the library holds, oldest first — in their own words.
The doxology "Glory be to the Father, and to the Son, and to the Holy Spirit" is of Christian antiquity; in the fourth century its co-equal, trinitarian form is pressed into general use against the Arians, who denied the full divinity of the Son.
The closing clause — "as it was in the beginning, is now, and ever shall be" (sicut erat in principio) — is a Western addition, affirming that the glory of the Son is eternal, and was not, as the Arians held, a glory that once began.
“Especially in the fourth century, as a protest against Arian subordination…, the custom of using the form: "Glory to the Father, and to the Son, and to the Holy Ghost", became universal among Catholics.”