What is the origin of the Gloria patri?

Answer 1

There are several variations, actually. One common one goes like this:

Glory be to the Father
And to the Son and to the Holy Ghost.
As it was in the beginning
Is now and ever shall be.
World without end, Amen.

Answer 2

the gloria patri was used to affirm the trinity againest the Arian heresey in the 300's which denied the diety of Christ