Chronology of Catholic Dioceses:Notes on the Diocese of Argyll, c. 1183 - 1560
The Diocese of Argyll was detached from Dunkeld between 1183 and 1189. Its territories included the western part of Dunkeld, and the Isle of Lismore where the cathedral was located.
The islands off the west coast of Scotland passed from Norway to Scotland in 1206. They were under the jurisdiction of the Archdiocese of Nidaros, Norway, until 1387, when they were detached from the Diocese of Sodor and Man. Soon after, possibly in the same year, this new diocese was united with Argyll, which was renamed Argyll and the Isles. The islands were reestablished as a separate diocese between 1418 and 1437, and Argyll took its old name back.
In 1552, William Cunningham, 16th Bishop of Argyll, passed away. James Hamilton was named as his successor, but sources indicate that he was never consecrated. The See survived in this provisional state until the Scottish Reformation in 1560.
In 1878, Pope Leo XIII re-erected the Scottish hierarchy, and Argyll and the Isles was detached from the Apostolic Vicariate of Scotland - Northern District on 4th March that year.
(Source: Catholic Encyclopedia, http://www.newadvent.org/cathen/01706c.htm)-CNy
