Alcuin of York (735-804) wrote in 797 to Higbald, Bishop of Lindisfarne, about the introduction of secular music and the harp (cithara) into the cloisters. Alcuini Epistulae, "The Letters of Alcuin") ed. Dümmler, (Monumenta Germaniae Historica, Epist. Karolini Aevi, ii), pp. 181 ff., quote on p. 183:
verba Dei legantur in sacerdotali convivio. Ibi decet lectorem audiri, non citharistam; sermones patrum, non carmina gentilium. Quid Hinieldus cum Christo?
... let the words of God be read in the gatherings of priests. There it is fitting for a reader, not a harp-player, to be heard; the teachings of the Fathers [of the Church], not the songs of the pagans. What is Ingeld in comparison to Christ? ]or, What has Ingeld to do with Christ?]
Ingeld is mentioned at Beowulf 2020-2069, Widsith 48, and Saxo Grammaticus, Gesta Danorum ["The Deeds of the Danes"] 6.182 ff.
See the Wikipedia page on Ingeld.
(From this page, 10.09.18)