The Clan is a concept which dates back to the 12th Century. The Scottish clans were originally extended networks of families who had loyalties to a particular chief, but the word 'clan' is derived from the Gaelic 'clann', meaning literally children.
In Scotland a clan is still a legally recognised group with an official clan chief. The chief's Seal of Arms, incorporated by the Lord Lyon's letters Patent, is the seal of the corporation and only the chief has the legal right to use the seal on behalf of his clan.
"For that is the mark of the Scot of all classes . . . there burns alive in him a sense of identity with the dead, even to the twentieth generation."
Clan names are usually associated with land: an area of Scotland where the clan lived. The clans lived off the land, with cattle being their main source of wealth and, along with border disputes, the prime cause of inter-clan unrest. The most important clan chiefs held power over the lands within their control, acting as a king, protector and judge.If a clan chief expanded territory, the new peoples swearing him allegiance often took the clan name. So, the history of clans is complex and interwoven and finding out which clan you belong to can depend on which era of history you're looking at. And there were many bitter rivalres and feads along the way, none of which have been carried through to the modern day, fortunately!
The clan system was the main political system in Scotland until the time of the battle of Culloden in 1746, when the Jacobite rebellion was crushed by the royal troops of King George II. The Highland Clearances were key to the ending of the clan system. Thousands of Scots emigrated to the New World, seeking a better life.
Many clans have their own tartan as well as a seal, and deciding which tartan to wear is often based on family history. For many families of Scots descent its hard to work out the appropriate clan as some surnames are Scotland wide, have variations in spelling or include words with etxra meaning for example 'Mac' means 'son of'. But most Scots or people of Scots descent can work out their clan with a little research into family history. The place where ancestors lived during the peirod when clans predomiated Scottish history, is usually the best guide as swearing allegiance to the local clan chief was commonplace.