The story goes that all the inventor asked for was to put a single grain of wheat on the first square (1), two (2) on the next square, four (4) on the third square, eight (8) on the next one and so on... the king was even offended a bit and he asked "are you sure that's what you want? I rule over the empire I can grant any wish you have, can give you gold and treasure". But the inventor modestly insisted so they started measuring out the grains...