The office of Captain of the Parish has its beginnings in the Manx defensive system of “Watch and Ward”. This was established here by Viking settlers between the eleventh and thirteenth centuries, but was not mentioned in writing until about 1420, when the Deemsters and Twenty-Four set down the ancient laws of Man for the Lord, Sir John Stanley II. Continuous Watch and Ward had to be kept, winter and summer, day and night, by “all manner of men”, the Day Watch post in each parish being on high ground, where beacons were erected, and the Night Watch near a possible landing-place.

At first, the defences were organised on a Sheading basis, but, by the 1490s, each parish had a Warden of the Watch, who at first was not only in charge of the Watch, but also of the whole parochial militia which mustered when the beacons were lit. A document of 1627 in the Castle Rushen Papers contains the names of all the Parish Captains and Wardens of the Watch. This shows that, at that time, the two offices were not necessarily held by the same persons. While the Captains were in overall command, the Wardens of the Night Watch were sometimes drawn from the garrisons of the Castles, while the Wardens of the Day Watch would usually be the owners of the headlands and hills with extensive views. (See list at end). It is believed that all able-bodied men from 16 to 60 were on duty in groups of four. Regulations of 1627 detail those who were exempt: the Captain, Lieutenant, Ensign, the 24 Keysmen, the Moars and their runners, the Coroners and their lockmen, the Customers (Customs Officers) and Searchers of every port, one head smith, and the head or chief miller in every parish. Every man had to bring his own weapons, and neglect of duty was severely punished. The system must have borne hard on parishes with small populations, but it continued to be enforced up to 1815. In this way, a “Home Guard” support force was provided for the garrisons of Peel and Rushen Castles, until they were disbanded at the Revestment (1765).

In the seventeenth and eighteenth centuries, when outside dangers threatened, special arrangements had to be made, as in 1689, when camps were set up at Hanmer Hould (Ballaugh), Shellag (Bride), Banks Howe (Onchan), Santon, Cass ny Hawin (Malew), and the Calf, and in 1720, when fears of the spread of plague from the Mediterranean meant extra watches being maintained to prevent unauthorised landings. In 1778, following a raid on Whitehaven by the Scottish-American privateer, John Paul Jones, the parish watches were called out three times a week. The Manx militia, numbering 4,181 men, was mustered for the last time during the Irish Rebellion of 1798.