Why do we have diamonds, hearts, clubs and spades on playing cards?

Answer 1

According to this website:
http://www.guardian.co.uk/notesandqueries/query/0,5753,-2647,00.html

Playing cards were invented by the Chinese before AD1000. They reached Europe around 1360, not directly from China but from the Mameluke empire of Egypt. The history of suitmarks demonstrates a fascinating interplay between words, shapes and concepts. The Mameluke suits were goblets, gold coins, swords, and polo-sticks. Polo being then unknown in Europe, these were transformed into batons or staves, which, together with swords, cups and coins, are still the traditional suitmarks of Italian and Spanish cards. Fifteenth-century German card-makers experimented with suits vaguely based on Italian ones, eventually settling for acorns, leaves, hearts and bells (hawk-bells), which still remain in use. Around 1480 the French started producing playing-cards by means of stencils, and simplified the German shapes into trefle (clover), pique (pike-heads), coeur (hearts), and carreau (paving tiles). English card-makers used these shapes but varied the names. Spade (pique) may reflect the earlier use of Spanish suitmarks, from espadas meaning swords, and clubs are what the Spanish suit of staves actually look like. Diamond is not only the shape of the paving tile, but may perpetuate connotations of wealth from the older suit of coins.