A coin dating from Alfred’s reign (871-99) was found on Tintagel island at the ‘chambers south of chapel’ site, probably by a visitor. The discovery may not have been made as part of an excavation. Its caption was given as ‘Tintagel 4/1/35 64a’. Number 64 indicates it was a pre-1938 discovery and 4/1/35 points to 1935.
“The coin is of a two-line type (BMC xiv), moneyer Beornmær, issued c 880-99, but its circulation outwith Wessex may suggest a depositon c 880-910.”
The following is an item on it from the British Numismatic Society:
The excavations between 1990 and 1999 text, Excavations at Tintagel Castle, Cornwall, has the following account:
The original chapel may well have been dedicated to Coliavus, see Coliavus, a name with Arthurian associations. One could speculate the coin was not an accidental loss but rather placed near the chapel if Tintagel had already been identified with Arthur in the 9th C and, perhaps, Alfred saw himself as the new Arthur.
Asser tells us Alfred visited Cornwall on a hunting expedition. This would have been some time before his marriage to Ealhswith in 868. He prayed at a church which held the body of St. Gueriir, which is now called St. Neot. Doble suggested the original saint was Gwinear, who was murdered by Teudur. That ruler is mentioned in the V. Petroci and the Beunans Meriasek. He also appeared in the V. Breacae, according to Leland. We may, therefore, conclude that Gueriir is likely to have been a contemporary of Arthur. Perhaps, therefore, Alfred had an interest in Arthur even before he became king, and later was his role model.
 Barrowman, R.C., Batey, C.E., Morris, C.D., 2007, 17.