The marriage of Black Duncan, the heir
When negotiating the marriage of the house's heir much more was at stake for Grey Colin and Kate. Significantly, all but one of the surviving letters were written to Kate and she was the prime mover in the matter.
Moving up the ranks
The Glenorchys pursued a common noble strategy of seeking to marry their eldest son to a woman of higher social status.
There was a strong case for concluding an alliance with the house of Atholl. Grey Colin's mother was the daughter of the 1st earl, making the 4th earl his relative and a marriage would bring a closer alliance with the most powerful magnate in the Perthshire region.
This would underline the eastward movement of the Glenorchy Campbells and assist in plans for further expansion.
For Atholl a marriage would maintain blood links and renew a political alliance with the Glenorchy Campbells. Since the earl had five daughters for whom to find suitable husbands and provide tochers, he could use their marriages to expand and strengthen his national and regional powerbase.
Apart from Jean who wed Black Duncan, Atholl's other daughters all married members of the Scottish peerage.
Jean had been betrothed to the earl of Angus in 1565 but probably due to changing political circumstances that alliance did not materialise.
When discussing marriages with Atholl, the Glenorchys were more supplicants than equals so Kate's close friend, William Maitland of Lethington, Mary, Queen of Scots' Secretary and a skilled diplomat who was asked to act as chief matchmaker.
Kate first suggested the possibility to Maitland, Atholl's brother-in-law, during the winter of 1566-7 (GD112/39/6/19). Things moved slowly because a group of Atholl's friends and advisers opposed the alliance and delayed its progress so that by the summer of 1570 Maitland was urging that terms be settled as quickly as possible.
He also reported the carefully-observed impressions of the prospective bride because Mary Fleming, Maitlands wife, had discussed the matter with her sister, Margaret, Atholl's wife (GD112/39/9/8).
The countess was fond of her step-daughter whom she treated as if she were her own daughter. Considerable care was taken to ascertain the suitability and mutual compatibility of the couple.
Although the initial attention was fixed upon Margaret, Atholls second daughter by his first wife, it was the younger sister Jean who actually married Black Duncan at Dunkeld in November 1573, though such changes were not unusual.
Maitland was the chief negotiator, but Atholl's right-hand man and brother-in-law, William Stewart of Grandtully, helped with advice on the size of the tocher and the 'going-rate' in the current marriage market (GD112/39/12/9).
The final stages required a written commission signed by both Kate and Colin along with an explicit written statement and an oral elaboration of acceptable terms (GD112/39/9/13 & 14).