Once a farmer had made up his mind on anything, it was very hard, if not impossible, to get it changed. This was especially true where money was concerned but of course this wasn't a bad thing at all and many deals were made with only a handshake and a good gob of spit to seal the agreement.
I once blotted my copybook by hearing about this ritual and trying to put it into practice without finding out the details. When trying to do a swap of my Meccano Set for a 1000 piece jigsaw, I had to make a speedy exit after shaking hands with the farmer's son and then spitting on him. I had the feeling it was wrong when I did it but seeing the look on his face was the clincher. I legged it.
It's a short journey from not wanting to change your mind and just being stubborn about it. When we knew someone who was in the wrong and knew that THEY knew it as well and still wouldn't change, then we'd describe them as being thran.
Thran : stubborn, being difficult.
It wasn't just adults who could be thran. A wilful, difficult child would be called thran too and because they could test the patience of a saint and stick to their guns despite all sorts of parental threats and/or entreaties, I heard this word used a lot to describe my contemporaries.
"Yon we'an is thran today, missus".
I, of course, was never thran. Not then, not now.
And you'll not change my mind.