The Scottish clan comprised a group of people who traced descent from a common ancestor and considered all members of the clan to be kin. The head of the senior line was chief of the whole clan, and branches of more closely related families within the clan were led by the head of the senior line within the branch. Fellow clansmen fought together and had war cries that were frequently shared by related clans or those that at some time had been allied against a common enemy.
The clan tartan is comparatively recent. In the 18th century the tartans of each locality were similar enough in pattern and color to differentiate them from tartans of other localities. By 1892 there were clan tartans. One of the Mac-pherson tartans was attributed to the wife of the great-grandfather of the then chief of the Mac-phersons. The modern clan tartans appear to represent chiefly tartans adopted in the 19th century as nostalgic clan symbols by Scotsmen who had become scattered all over the world.
Scottish clan genealogies normally trace descent through the father's line; that is, they are patrilineal. But on occasion an ancestress appears as a link in genealogy. For example, the Campbell clan takes its name from the Anglo-Norman Gillespie Campbell, who married Eva, heiress of the O'Duins. The clan consisted of the kin of the O'Duins, and in the clan genealogy Eva O'Duin figures prominently. Her son gave the name "Campbell" to the clan.
A clan had an established territory, and the feelings of kinship and common residence were closely associated. The Campbells expanded into the territory of several smaller clans. Since most of these disappeared from the records, one must infer that the clans whose territories were taken over by the Campbells became Campbells.
The clan type of structure, in which people are organized in genealogical kin units which are also political and territorial units, survived longer in Scotland than in most parts of Europe, but early records show that the tribal Latin gens and Germanic sibb were like the Scottish clan. In tribal Central and Southwest Asia, this type of genealogical kin group is still found.