"I wanted to try this new drink. That's all we do, isn't it—look at things and try new drinks?" —"Hills Like White Elephants," Men Without Women, 1927
There is much to support the Old Fashioned's claim to be the original cocktail. In fact if you take your definition of 'cocktail' from The Balance and Columbian Repository of Hudson, New York (and frankly, where else are you getting your definition of cocktail from?) it neatly fits the criteria: liquor (in this case whiskey), bitters, sugar and water (in this case frozen).