261 — a grid reference? A page number? A year (AD 261, when Rome was crumbling and British tribes whispered old names)?
This looks like a coded or structured string: "thmyl-fyd-myt-asdar-261-llandrwyd" . thmyl-fyd-myt-asdar-261-llandrwyd
An old poet from Caernarfon, when shown the text, laughed darkly. “That’s no code,” he said. “It’s a spell broken. ‘Thmyl’ is a mishearing of ‘thymial’ — thimble. ‘Fyd myt’ — ‘my foot’ in a dialect dead four centuries. ‘Asdar’ — as in ‘as darllen’ — ‘for reading aloud’. And 261 steps from the old Llandrwyd well to the yew tree.” 261 — a grid reference
“And if you walk those steps at midnight, speaking the words backward?” when shown the text