The Syllanine Order was a Cornish monastic order that ruled the Isles of Syllan, or Scilly, for some centuries. The order was first organized c. 930 and formally recognized by Pope Benedict VIII in 1018.
The order used a seal from its early days that took the form of one variety of ringed Celtic cross used in Kernow, with small circles representing the isles. During the Crusading era the seal was formalized as a coat of arms, making it one of Europe's oldest heraldic symbols. It was colored blue for the sea, and the writing that had appeared around the outer ring was removed. The arms are blazoned: "Azure, within an annulet argent a cross patée-alisee argent between four plates."
From http://althistory.wikia.com/wiki/Syllanine_Order_%28Ethelred_the_Pious%29
The order used a seal from its early days that took the form of one variety of ringed Celtic cross used in Kernow, with small circles representing the isles. During the Crusading era the seal was formalized as a coat of arms, making it one of Europe's oldest heraldic symbols. It was colored blue for the sea, and the writing that had appeared around the outer ring was removed. The arms are blazoned: "Azure, within an annulet argent a cross patée-alisee argent between four plates."
From http://althistory.wikia.com/wiki/Syllanine_Order_%28Ethelred_the_Pious%29