(Photo: Glasgow Vennel, Irvine. Source here)
Following on from the previous post, in the book Muniments of the Royal Burgh of Irvine, Volume II (published 1891), there are more details of Irvine's connections to Ulster.
The accounts include both the illegal smuggling of "Irish Cloaths", and the legal trading of Ayrshire-mined coals into Ireland. On 26 May 1665 James Porter was appointed as a Burgess of Irvine - his father, Hew Porter, was a Burgess in Lochlerne (Larne?). Two years later on 13 May 1667 James Cleland, former Provost of Bangor, was also appointed as a Burgess of Irvine. The Burgh accounts for 1601-1602 include a reference to a "William Wilsoun, travellour in Ireland" (the same period when Hugh Montgomery was famously trading between Ayrshire and Carrickfergus). On 18th April 1681 the Irvine town Treasurer, Robert Brysone, was ordered to pay David Buchanan "nynteinth pounds Scotts" for his work on repairing the town clock - Buchanan had to do the work because William Weir (presumably the man who should have done the work) had "went to Ireland".
All fairly unspectacular stuff - which is the whole point. The links across the sea, between the two coastlines, and among what was/is one cultural community were/are ordinary. The Ulster-Scots connection is natural, ordinary - and, paradoxically, that's what makes it special.