Dineley's "Observations on a journey" 1681,describes this inscription thus:Hic jacet bone sue Franciscus Tobyn burgisia et mayor ville de Yoghall qui obit decimo septimus Aprilis Anno Domini MDLI.
On the wall overhead this flagstone is a modern plaque which reads " The oldest stone having a date.Here lies the worthy Francis Tobyn, burgess and Mayor of the town of Youghal, who died on 17 April 1557."
Note: In roman numerals, M=1000, D=500,L=50,i=1, so MDLI is 1551 ,not 1557.
According to the sketch of the stone in Dineley's work, the date was inscribed inside the circle which is now illegible.