The Gloria or the Great Doxology (hymnus angelicus) is an
ancient prayer of the Mass and is a version of a very old Greek
form of the Liturgy. So, to answer the question of who wrote the
Gloria it was the Early Churchs , i.e. those set up by the Apostles
as the Spread the Gospel - the Good News. The tradition is that it
was translated into Latin by St. Hilary of Poitiers (d. 366). It is
quite possible that he learned it during his exile in the East
(360) and brought back a version of it with him. - Information from
the Faith Data Base The Catholic Encylodedia.
Here are the Biblical Refernces to the Gloria:
Glory to God in the highest and peace to his people on earth.
[Glory to God in the highest and on earth peace to those on whom
his favor rests. (Luke 2:14)]
Lord God, heavenly King, Almighty God and Father. [Alleluia! The
Lord has established his reign, our God the almighty! (Rev
19:6)]
We worship you, [Worship God. (Rev 22:9)]
We give you thanks, [. . . giving thanks always and in
everything in the name of our Lord Jesus Christ to God the Father.
(Eph 5:20)]
We praise you for your glory. [Amen! Blessing and glory, wisdom
and thanksgiving, honor, power and might be to our God forever and
ever. Amen! (Rev 7:12)]
Lord Jesus Christ, only Son of the Father, [Grace, mercy and
peace will be with us from God the Father and from Jesus Christ,
the Father's Son in truth and love. (2 John 3:)]
Lord God, Lamb of God, you take away the sins of the world; have
mercy on us; [Behold the Lamb of God, who takes away the sins of
the world. (John 1:29)]
You are seated at the right hand of the father, receive our
prayer. [It is Christ Jesus who died, rather, was raised, who also
is at the right hand of God, who indeed intercedes for us. (Rms
8:34)]
For you alone are the Holy One, [I know who you are-the Holy One
of God. (Luke 4:34)]
You alone are the Lord, [Who will not fear you Lord, or glorify
your name? For you alone are holy. All nations will come and
worship before you. (Rev 15:4)]
You alone are the most high Jesus Christ, [He will be great and
will be called Son of the Most High. (Luke 1:32)]
With the Holy Spirit, in the glory of God the Father. [The
Advocate, the Holy Spirit that the Father will send in my name. . .
(John 14:24)]