Hello,
I have tried to research these Lairds beyond Alexander Laird b1580 and appearing in church of Scotland records in the parish of Eassie, Perthshire (less than a mile from Castle Glamis) and have been doing some guessing after lots of search results were showing 'Laird' as a title rather than as a surname. With having a few Alexander Lairds in my tree, I noticed that the Irwin/Irvine Lairds of Drum had a tradition of naming the oldest male Alexander. Although not convinced, I followed Sir Alexander 10th Laird of Drum b1596 back and found a well documented line back through the Lairds of Drum, Aberdeenshire. They'd been granted lands up there by Robert the Bruce and were first known in Dumfriesshire. Actually that line goes back to King Duncan via King Malcolm III and Saint Margaret, then a long list of Ui Neil monarchs of Ireland. I'd be interested to know what you think of all this, what with it being Aberdeen, not Perthshire and a somewhat tenuous link with the uncertainty of birth date (1580/1596 - same person or father and son?).
https://en.wikipedia.org/wiki/Clan_IrvineI then researched more recent Laird wives to see if I could get anything else to perhaps lend weight to the Irwin idea and found a lot of interesting stuff. The Cowans (mentioned earlier) and Ruthven (via a Murdoch wife) are particularly interesting. The Ruthvens are linked to Huntingtower Castle...
https://en.wikipedia.org/wiki/Huntingtower_CastleIt seems they lost their castle to the Crown, only for it to eventually fall into the hands of the Cowan family (who farmed there up until 2002, apparently). Margaret Cowan b 1688 married Robert Laird b1687 (who's gg1 was Agnes Ruthven b1611) - therefore it would seem those Ruthvens retook their castle through marriage.
I have been able to trace all Laird wife lines back quite far but it is frustrating not knowing for certain what this Alexander Laird b1580's story was.