The Commonwealth created the Postmaster-General's Department on 1 March 1901, which took over all the colonial mail systems and the then-current colony stamps. These stamps continued to be valid and became de facto Commonwealth stamps. Some of these stamps continued to be used for some time following the introduction in 1913 of the Commonwealth's uniform postage stamp series. These stamps continued to be valid for postage until 14 February 1966 when the introduction of decimal currency made all stamps bearing the earlier currency invalid for use.