The 90º Crossed Keys are part of many Heraldic Crests throughout England and Scotland. Unfortunately every one of these references uses a St. George's Cross (Perfect 90º X Shape) and many people believe the angle is important to the origin.
The Crossed Keys are part of the Symbol used by the VATICAN, but in that case the angle is lower, and topped by a Miter (the pointed, clerical hat worn by church officiants).
In fact, the crossed keys are part of the Heraldic symbol of Pope Benedict XVI. Again, though, these are either at 90º or at a more 'flat' angle. These Crossed Keys, though are at an angle that is equivalent to a type of St. Andrew's Cross which is aligned with, and related to, the constellation Orion, a symbol of great antiquity, probably Neolithic.
John are you sure this Roman Mosaic is 14kt gold and not gilded?
The reason I ask is because, the crossed keys and miter was used in ROME, ITALY on SILVER - ca 17th Century.
As early as the 17- 18th century the Vatican was making pieces of Roman mosaic jewelry to sell to visitors. The Mosaics made in Rome have an entirely different look from those made in Florence.
It was in 1870, the conquest of Rome marked the end of Stato Pontificio (Papal State). Italy attained its unity along with a unique system of hallmarking, introduced in the Regno d'Italia (Kingdom of Italy).
