When was the first stamp issued?

Answer 1

From Wikipedia..... Although there have been several claimants to priority, it is generally held that postage stamps were first introduced in the United Kingdom of Great Britain and Ireland in May 1, 1840 as part of the postal reforms promoted by Rowland Hill. With its introduction the postage fee was now to be paid by the sender and not the recipient as heretofore, though sending mail prepaid was not a requirement. The first postage stamp, the Penny Black, while put on sale on the 1st of May, was postally valid from May 6, 1840; two days later the Two pence blue was issued. Both stamps show an engraving of the young Queen Victoria and were an immediate success though refinements like perforations were instituted with later issues. At the time of the Penny Black, there was no reason to include the United Kingdom's name on the stamp, and to this day the UK remains the only country that does not identify itself on its stamps.