Comment by dghf

But the graphic suggests that Celtic Christianity was in some sense theologically distinct from Chalcedonian Christianity, and that doesn't seem to have been the case. The main ways that the Christians of Ireland and Britain differed from those of continental western Europe seem to have been in the shape of the monastic tonsure and the calculation of the date of Easter; and in the latter, at least, British and Irish Christians were in conformity with Rome by the end of the eighth century. (There was also an emphasis on penance and absolution as a private rather than public rite, but this was ultimately adopted by the wider church.)

There doesn't seem to have been any doctrinal disputes, nor any suggestion that British and Irish Christianity was in any way separate from the Church of Rome.