The roots of the island’s Welsh name, Ynys Môn, are something of a mystery. Ynys simply means island. But the meaning or identity of Môn are unclear. The Romans knew it as Mona, the Saxons as Monez. But if this was a person, their identity has been lost over time. The English name derives from Old Norse. It could mean either ngullsey, hooked island, or nglisey, ngli’s island. No character by the name of ngli has ever been traced, however.