It has generally been accepted as an axiom that the date of a seal can be determined within close limits by the style of the lettering of its legend. The late G. Demay, in his Inventaire des sceaux de la Normandie, published in 1881, was the first to give serious attention to the subject, and he naturally drew his material almost entirely from French sources. In 1887 the late Sir William Hope, in his paper on the Seals of English Bishops, offered some suggestions as to the date of the different styles of lettering, basing his conclusions on the fact that a bishop's first seal must be of the same date as his appointment to his see. His classification was as follows:

(1) 1072-1174. Roman capitals.

(2) 1174-1215. Rude Lombardic.

(3) 1206-1345. Good Lombardic.

(4) 1345-c. 1425. Bold black letter.

(5) c. 1425-1500. Fine close black letter.

(6) After 1500. Roman capitals.