The Visa card was originally set up as the BankAmericard as a Bank of America exclusive card, later, to compete with Mastercard's forerunner, Mastercharge (which was started by a 4 bank consortium in California and then expanded to other banks in the west), it opened up membership to other banks and changed its name to Visa. MC and Visa share the same basic infrastructure and charge the same fees, which is why you usually see them both here in the States.

One other tidbit: there are quite a few places throughout Europe that take Visa/MC that haven't ever updated their credit card stickers in the shops, so you see that they take BankAmericards and Mastercharges (the logos are very similar to today's logos).