According to a former port authority of Leixões, the Count of Vilas Boas, an individual stole a compass in Póvoa de Varzim and tried to sell it in Matosinhos, but he was unaware that the recorded "drawings" in the cover indicated the owner's name and thus the first person whom he approached (a woman from Póvoa de Varzim) managed to recognize the mark immediately.
The alphabet derived from Cyrillic and Greek, and Komi tribal signs, the latter being similar in the appearance to runes or siglas poveiras, because they were created by incisions, rather than by usual writing.