What does it mean to call Christ the "Firstborn"?

A Look at Col 1:15

15 The Son is the image of the invisible God, the firstborn over all creation. 16 For in him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers 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 And he is the head of the body, the church; he is the beginning and the firstborn from among the dead, so that in everything he might have the supremacy. 19 For God was pleased to have all his fullness dwell in him, 20 and through him to reconcile to himself all things, whether things on earth or things in heaven, by making peace through his blood, shed on the cross.

In this poem, Paul argues that Christ is God’s supreme agent in creation and new creation. Of course, one enduring question has been how to understand the reference to Jesus as God’s “first-born” in v. 15 (the Greek word is prōtotokos). For some interpreters, I think here of the fourth-century Arians, it meant that Jesus was God’s first-made-creature of creation. In other words, Jesus was a brilliant angelic being, above all of creation, but still below God in rank and level of divinity.

What supports the Arian reading is identifying Christ with God’s wisdom. Much of what is said about Christ in this poem is also said of God’s wisdom. Jewish texts oscillate between treating wisdom as something created by God (Prov 8.22; Sir 1.4; 24.9) or an emanation of God (Wis 7.25-26). Accordingly, if the first stanzas of the poem emerged from a christological reading of Gen 1.1 and Prov 8.22-23, then, it remains possible that Christ’s priority to and preeminence over creation are concurrent with his own creatureliness of some heavenly variety. Arius was not clutching at straws; you can appreciate how his argument had some textual traction.

However, what mitigates against that the Arian reading of Christ as a heavenly creature is several things:

(1) There are better words besides prōtotokos that could be supplied if Paul wanted to refer to Christ as an angelic creature, such as prōtoktistos (“created first”), prōtoplastos (“first formed”), prōtogonos (“first generated”), prōtosystatos (“primordial”), prōtochronos (“first in chronology”), or prōtopresbyteros (“first ancient being”). In all likelihood, Paul deploys prōtotokos because of its association with Israel (Exod 4.22-23; Sir 36.17) and the Messiah (Ps 89.27), to make the Jesus the eschatological ruler of Israel, not for a connotation of creatureliness;

(2) In 1.16, Christ is not part of ta panta “all things,” the poem distinguishes Christ from other angelic powers and heavenly intermediaries, the same distinction that generally separates God from creation and angels in other Jewish and Christian writings (e.g. Isa 44.24; 66.1-2; Sir 24.8; 1 Enoch 9.5);

(3) Two unique aspects are also attributed to Christ in the poem: first, that creation was made “for him” (1.16); second, that God’s “fullness” inhabits him (1.19), neither of which are attributed to lesser angelic powers as far as I am aware.

The christology of the poem is sky high, through a mixture of messianic and wisdom themes, Paul argues that Jesus is God’s supreme agent in creation, new creation, head of the church, and far superior to all angelic orders. In fact, Paul goes so far as to claim that the fullness of God - that is God’s word, wisdom, glory, Spirit, and power - dwell in the Messiah.