What do Protestants make of the earliest Marian prayer?

The earliest known prayer to St. Mary is called Beneath Thy Protection (Sub tuum praesidium), and it is commonly dated around mid third century (~250 AD), or as late as fourth century. From the Wikipedia link are four translations. This is the one taken from the Greek: > Beneath your compassion, > We take refuge, O Theotokos [God-bearer]: > do not despise our petitions in time of trouble: > but rescue us from dangers, > only pure, only blessed one. What do Protestant Churches make of this fact? How do they explain the early apparition of the prayer?