[1] The stone was discovered in 1911 during the excavation of a chapel at Knock y Doonee in the parish of Andreas on the Isle of Man.
The stone is made from 'clay slate', and is believed to have originated from hills six miles to the south of the site where it was found.
[2] It has the designation CIIC 500 in R. A. Stewart Macalister's Corpus Inscriptionum Insularum Celticarum (1945).
The Latin and Ogham inscriptions are dated to the 5th or early 6th century, and both commemorate a person named Ammecatus son of Rocatus.
The names Ammecatus (or Ambicatos) and Rocatus (or Rocatos) are both Celtic, but it is unclear whether they are Irish or Brittonic.