In 1980 ARPANET was linked to the University of Essex, Colchester, England, where two undergraduate students had written a text-based fantasy adventure game that they called MUD, or multiuser dungeon.  When the first outside users connected to MUD through ARPANET, online gaming was born.

History of gambling houses\n\n The first known European gambling house, not called a casino although meeting the modern definition, was the Ridotto, established in Venice, Italy, in 1638 by the Great Council of Venice to provide controlled gambling during the carnival season.