The Motto is a saying associated with the family that can be part of the coat of arms. Not every coat of arms has a motto, and the rules governing the status of the motto varies from country to country. In England for example the motto is never mentioned or alluded to in the terms of a patent in a grant of arms and mottoes are not hereditary. However in Scotland the motto is included within the terms of the patent and is consequently made the subject of the grant. This makes it an unchangeable part of the coat of arms, and it Scotland, the position of the motto is also specified, usually above the crest. In Ireland the custom is different again, sometimes the motto is expressed in the grant of arms and other times it is not and there is no hard and fast rule.
The motto is the subject of much confusion among modern commentators on heraldry. There are countless references to family mottoes in romance and we are usually told that the motto originated at some remote period of the family history, and had a definite allusion to the family fortunes or to family character, or in some way meant a great deal. It is true that some mottoes must have originated in this way, and some even as war cries, like the “Crom a boo”of the Fitzgeralds( Meaning “Crom forever”, Crom being the castle of the Fitzgeralds ). Mottoes are in most cases of late adoption, are quite unsuitable for war cries, and have no more historic allusion than any other respectable matter within a particular family.
The Composition of the Coat of Arms part 5, The Motto.