Saint Eligius (590-660 CE) was the Bishop of Noyon-Tournai and engaged in missionary activities in his native France. We learn something of the beliefs he was countering, which many Christians obviously also adhered to at least in part, through the text of a sermon of his from 640 CE:
Before all things I declare and testify to you that you shall observe none of the impious customs of the pagans, neither sorcerers, nor diviners, nor soothsayers, nor enchanters, nor must you presume for any cause to enquire of them…
Let none regulate the beginning of any piece of work by the day or by the moon. Let none trust in nor presume to invoke the names of dæmons, neither Neptune, nor Orcus, nor Diana, nor Minerva, nor Geniscus nor any other such follies…
Let no Christian place lights at the temples or the stones, or at fountains, or at trees, or at places where three ways meet… Let none presume to hang amulets on the neck of man or beast… Let no one presume to make lustrations, nor to enchant herbs, nor to make flocks pass through a hollow tree, or an aperture in the earth; for by so doing he seems to consecrate them to the devil.
Let none on the kalends of January join in the wicked and ridiculous things, the dressing like old women or like stags, nor make feasts lasting all night, nor keep up the custom of gifts and intemperate drinking. Let no one on the festival of St. John or on any of the festivals join in the solstitia or dances or leaping or caraulas or diabolical songs.
This section of the sermon is quoted in Chapter 1 of Eleanour Sinclair Rohde’s book The Old English Herbals, which can be read online here.