Pertuis was a Roman fortress guarding a pass through the Pyrenees into Ispania. In the spring of 1315 the Franco-Saxons succeeded in storming the fortress with the aid of their hellpowder. After looting and burning, the Franco-Saxons left the ruins unoccupied as they advanced further into Ispania.
That fall, the magistrianos Basil Argyros came to the fortress to see if he could learn anything about the Franco-Saxons' methods. There he found a number of potsherds that were of a uniform yellow-brown clay and blackened on one side as if exposed to fire. Several carried the potter's mark of the Monastery of St. Gall which was in the far off Alps.
After camping overnight, he was discovered by Wighard and Hilda, two Anglelanders he had met previously in New Carthage. The three found that they had been sent by their respective rulers and had a common interest. They agreed to travel together to St. Gall.
- See e.g. Agent of Byzantium, pgs. 124-125, 130, tpb.
- Ibid., pgs. 129-131.
- Ibid., pgs. 131-134.