Ancient Greeks and Romans made crude dice from animal bones, various stones, minerals, and ivory. When they were tested mathematically, some were found to be quite accurate.
A mathematician named Jerome Cardan (1501-1576) used his talents in mathematics and probability theory to make his living as a gambler. He is thought to be first person to formulate the definition of classical probability.
During the mid 1600s, a professional gambler named Chevalier de Mere made a considerable amount of money on a gambling game. He would bet unsuspecting patrons that in four rolls of a die, he could get at least one 6. He was so successful at the game that some people refused to play.
He decided that a new game was necessary to continue his winnings. By reasoning, he figured he could roll at least one double 6 in 24 rolls of two dice, but his reasoning was incorrect and he lost systematically. Unable to figure out why, he contacted a mathematician named Blaise Pascal (1623-1662) to find out why.
Pascal became interested and began studying probability theory. He corresponded with a French government official, Pierre de Fermat (1601-1665), whose hobby was mathematics. Together the two formulated the beginnings of probability theory.
Source - Allan G. Bluman. Elementary Statistics: A Step By Step Approach.
Today probability theory is applied in vast verity of industries such as math, statistics, gambling, computer gaming, commerce, even in politics.