The custom of fosterage, common in Ireland and the Scottish Highlands, could be the subject of formal agreement, sometimes but not always committed to writing as a signed contract. By this practice, the children of a clan chief or cadet branch were brought up in the household of one of the leading men of the clan or a neighbouring chief or cadet; but there is a Fraser example of fostering of a younger son of Lovat (by a daughter of the Earl of Moray) by a quite obscure tenant in the Abertarff area, far from his home in Beauly.

The best known contract of the kind, the original of which in Gaelic is still preserved in the National Archives of Scotland, deals with the fostering of Norman MacLeod (later Sir Norman of Berneray), third son of Sir Rory mor of Dunvegan, by a Campbell family in Harris. It was drawn up in 1614, and most of the recorded examples date from the sixteenth and seventeenth centuries. Of course, no money payment was involved, but it was usual for the child's father to supply the foster-parents with a specified number of cattle or other livestock, and at the end of the period - which generally lasted for seven years - an equal number were given by the foster-father to the fosterling.

Responsibility for the maintenance and early training of a chief s son was deemed a privilege, and it resulted in a close bond between the foster family and the fosterling. It helped to knit the clan together, and many examples are related of devotion to their charge in later life by the foster-father and foster-brothers - to Maclean of Duart at the Battle of Inverkeithing ('another for Hector') and to Cameron of Lochiel at Killiecrankie, for instance. As late as the eighteenth century, two Fraser soldiers went out of their way to accompany their officer foster-brothers, one on a dangerous night patrol with the Black Watch in Holland, and the other on war service in the American Revolution.

In bringing up a young child, the foster-mother would play an important part, and in some cases she too was named in the contract. Clothing had to be provided, as we know from the account of expenses incurred in fostering Archibald Campbell, the future ninth Earl of Argyll, by Sir Colin Campbell of Glenorchy and his wife Juliana (daughter of Lord Loudoun).

No written contracts of fostering among the Munros is known, but that the custom was followed in the chiefs family is suggested by mention of the foster-mother of Hector, younger son and successor of Robert mor Munro of Foulis; she was named as Christian Neill Dayzill in the trial in 1590 of Mr Hector on suspicion of dealing in witchcraft - the surname is a Lowland one, and is not otherwise known in connection with the Clan Munro.