Matrices of steel and iron were made at a later time in the 16th and 17th centuries.
This was successfully accomplished by the use of flexible paper matrices, from which metal plates could be cast in shaped moulds to any desired curve.
In the 11th century a fairly large number of matrices were cut in ivory.
In the British Museum are the bronze matrices of seals of ZEthilwald, bishop of Dunwich, about Boo; of lElfric, alderman of Hampshire, about 985; and the finely carved ivory double matrix of Godwin the thane (on the obverse) and of the nun Godcythe (on the reverse), of the beginning of the 11th century.
In the later centuries also, particularly in the 14th century, they were set in seal matrices and finger rings.
