The earliest church on the cathedralCathedral (Latin cathedra' throne') Church which contains the throne of the bishop and hence the mother church of the diocese site was probably founded after c.907, as a monasteryMonastery The house of a religious community which held the relics of the Anglo-Saxon princess St Werburgh. There is definite documentary evidence of a major church on this site in 958, when English rulers were re-establishing both Christianity and their own authority in the area after devastating VikingViking Customarily refers to the Scandinavian explorers, warriors, merchants, and pirates who raided, traded, and settled in wide areas of Europe and the North Atlantic islands from the late eighth to the mid-eleventh century.There is some debate over the meaning of this word, which is attested but rarely used in the early medieval period. It was revived as a term in Scandinavian languages in the 17th century and in English in the early 19th. In contemporary sources it refers to a raider or pirate, often in association with ships and predatory activity. Some modern scholars try to keep to this restricted definition; others are happy with a wider range of meaning, applying the word to Scandinavians and their culture from approximately 790 to the mid or late 11th century, especially outside the Scandinavian homelands. raids. This Anglo-Saxon church was completely destroyed in 1090, but St Werburgh’s relics were placed in a new Benedictine monastery on the same site. This became Chester Cathedral in 1541.
References: Victoria County History of the County of Chester 5 Part 1: Chester, pp. 16-33.