Did St. Paul know the doctrine of the Trinity? Did St. Paul know anything about the doctrine of the Trinity (3 Persons in 1 God) but ran out of ink to fully explain it?

Or would the Trinitarian doctrine of the Athanasian Creed, for example, have been news to him if he lived in the 4th century?
Taken from St. Pauls writings: 

For in Him (Jesus)all the fullness of Deity dwells in bodily form Col 2:9

Perhaps one of the clearest indications that Paul thought Jesus was Yahweh comes from the fact that he used Monotheistic Old Testament passages which uniquely referred to Yahweh and applied them to the Lord Jesus Christ (Romans 10:13 cf. Joel 2:32; 1 Cor. 1:31 cf. Jer. 9:24; 1 Cor. 2:16 cf. Isa. 40:13; 1 Cor. 10:26 cf. Ps. 24:1; 2 Cor. 10:17 cf. Jer. 9:24 for just a few examples).  1 Corinthians 2:16, for example, alludes to Isaiah 40:13 which is in the context of some of the most explicit monotheistic statements in the entire Old Testament (cf. Isaiah 40:13-28; 43:10; 44:6, 8; 45:5).

Paul also described Jesus as Creator, "Yet for us there is but one God, the Father, from whom are all things and we exist for Him; and one Lord, Jesus Christ, by whom are all things, and we exist through Him." (1 Cor. 8:6).

15 He is the image of the invisible God, the firstborn of all creation. 16 For by Him all things were created, both in the heavens and on earth, visible and invisible, whether thrones or dominions or rulers or authorities—all things have been created through Him and for Him. 17 He is before all things, and in Him all things hold together. 18 He is also head of the body, the church; and He is the beginning, the firstborn from the dead, so that He Himself will come to have first place in everything. 19 For it was the Father’s good pleasure for all the fullness to dwell in Him, 20 and through Him to reconcile all things to Himself, having made peace through the blood of His cross; through Him, I say, whether things on earth or things in heaven. Col 1:15