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.
Examples of seals, both matrices and impressions, are found among the antiquities of Egypt, Babylonia and Assyria.
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 11th century a fairly large number of matrices were cut in ivory.