Although a number of people laid claim to the concept of the postage stamp, it is well documented that stamps were first introduced in the United Kingdom on 1 May 1840 as a part of postal reforms promoted by Sir Rowland Hill. With its introduction, the postage fee was then to be paid by the sender and not the recipient, though it was still possible to send mail without prepaying. Postmarks have been applied over stamps, "obliterating" them from further usage, since the first postage stamps came into use.