I found an interesting post showing the surviving fragment of the oldest known hymn to Mary. Here’s a summary of the facts:
The fragment of Papyrus is in the Rylands Library, in Manchester UK. The earliest text of this hymn was found in a Christmas liturgy of the third century. It is written in Greek and dates to approximately 250 A.D.
Here is the text in English:
Beneath your compassion we take refuge, Theotokos! Our prayers, do not despise in necessities, but from danger deliver us, only pure, only blessed one.
Theotokos mean “god bearer”. The hymn is clearly a prayer to the blessed virgin asking for her intercession and assistance in time of trouble. It is a written record of what must have been an earlier practice. Because the hymn was included in the liturgy, it must have been approved of by the church.