New here - need help with understanding Clans

[O'Callaghan]

Yes, both points are correct. There are many Davidsons -- particularly in the 'New World' -- who would like to think they are related to each other in some distant way, but this is obviously incorrect. Just as not all those who bear the name Robert-son, John-son, Hender-son are related. The only ones who can correctly refer to themselves as members of Clan Davidson are those who are descended from Davidsons in Lochaber, Badenoch, Strathdearn and Petty (and, latterly, Easter Ross). But that's set aside these days in favour of the Society system which is based on name and not on descendency.

As for the Clan Chattan this confederation was dissimilar to other 'confederations', such as Macdonald, only in that the individual clans kept their individuality; they did not become merely a part of the whole. Several times in history this was reinforced by way of bonds of friendship and relationship to strengthen what would otherwise have made them weak. And, of course, they intermarried all the while retaining their patronymic. Today the chiefs of those clans are all part of the society bearing common identity as Clan Chattan.

But the designation of those chiefs is important to note: Mackintosh of Mackintosh (that is, of the whole name, despite its various spellings), Macpherson of Cluny (there are Macphersons unrelated to the clan in the Central Highlands), Farquharson of Invercauld (a territorial differentiating him from other Farquhars), Macthomas of Finegand (no relationship to Macthomases in the West Highlands), Shaw of Tordarroch (there are many unrelated Shaws in other parts of Scotland and in England), Maclean of Dochgarroch (also referred to as Macleans of the North and Clan Tearlach), and Davidson of Davidston. MacBain of MacBain is chief of all of that distinct spelling of the name, but not of all Macbeans. There are other clans within the Clan Chattan currently without chiefs. When the Macphail chief is found and acknowledged by Lord Lyon, he will not be Macphail of Macphail because there other Macphails and Pauls from other regions in Scotland.

As for the Clan Chattan tartan, this was one of two designs by Wilsons of Bannockburn in the early 19c, both called Mackintosh: one from much earlier has become well known as the Mackintosh, the other as Clan Chattan with no particular connection with Mackintosh. This is a simplified explanation, I know, but a more complete one needs it's own thread.

My wife was told she was Clan Davidson by her Scottish grandmother, maiden name Davidson but then living just across the border in England, before the latter died [ETA: Oops! I see I already said that]. In most cases, even in Scotland, this is as close as most people will get to being able to prove that they belong to a particular clan.

As my wife was never told anything about the Clan Chattan Confederation by her grandmother, she declines to claim it.

Ironically, her grandfather was a Wilson, but English, not Scottish, and of no known Scottish provenance, although as we know there is no Wilson clan and nor is it a sept of any clan [ETA: I see from above in this thread that Wilson is now regarded as a sept of Innes, but that wouldn't include English Wilsons, unless of Scottish descent, because that's not how it works]. However, as I'm sure you know a Scottish Wilson owned the first ever commercial tartan mill, so of course there is a Wilson tartan, simply because they owned the mill! [ETA: Moreover, as thrifty Scots, I'm sure they would have been more than happy to take the money of Sassenach Wilsons who wanted to wear it!]