[ArrogantBustard]

You could actually make a good case that Ireland and St. Patrick used to be Orthodox. [rather than Catholic]

In St. Patrick's day, there was no such distinction.

[redgolum]

Very true, but when the Easter celebration was held was a bone of contention between the Latin West and the Greek East even then. In fact, some of the English viewed the Irish as heretics because they didn't keep Easter in the Western way (Bede's Church History of the English People). Although, it must be said, Rome officially didn't get that worked up about it at that time.

[Kolokotronis]

Certainly there was no distinction made between "orthodox" and "catholic" in the days of our great saint, but it is fair to say that the Church among the Celts was definitely more tied to the East than to Rome. There was a well known connection between the monastery at Iona and the monastery at the Great Oasis in Egypt. The Liturgical practices of the Celtic Church were more Byzantine in form than those of Rome and the rest of the West and the bishops, monasteries and monastic missionaries acted quite independent of Rome. Because they couldn't match the rigors of Egyptian desert monasticism, they developed two other forms which they called green and white martyrdom, the former being life as a hermit on some mountain top, the latter heading off into "the white", to convert the heathen and never return to the home island. These very holy and brave monks converted most of Northern Europe up to and including Lithuania. That all pretty much ended at the Council of Whitby in 664. Even after that, many practices of the Celtic Church, including married clergy continued into the 11th century. Here's a link to a brief article on the Council of Whitby:
http://www.crc-rostrevor.org/resources/history/hist_p04.htm