In the early days of mixing drinks, a cocktail was defined as any spirit with sugar and bitters added. The Old Fashioned only became known as such when bartenders started making other concoctions with multiple ingredients. If a patron didn’t want to drink the new fancy concoctions they would say “I’ll have it the Old Fashionedway.” And so the Old Fashioned is often credited as the father of all cocktails.
Ah, the 'good ol' days.' Cigarettes were healthy. White bread had vitamins. Dad read the newspaper while mom folded laundry. The kids played with a puppy in the front yard. America was clean as a whistle and nobody asked any questions.