Whitby, Synod of, called by King Oswy of Northumbria in 663 at Whitby, England. Its purpose was to choose between the usages of the Celtic and Roman churches, primarily in the matter of reckoning the date of Easter (see calendar; Celtic Church). Among those involved in the synod were Cædmon, the poet, and St. Hilda, the abbess of Whitby, who favored the Celtic usages. St. Wilfrid, Abbot of Ripon was the chief spokesperson for the Roman usages. Oswy decided for the Roman usages and in so doing determined that the English church would be associated with the Roman in the main stream of Western European Christianity. Only a few of the Celtic clergy returned to the monastery of Iona and to their old ways. The traditional date (from Bede) of 664 has recently been interpreted as Sept. or Oct., 663.