Where it was invented: According to legend, the Sazerac was born at Antoine Amédée Peychaud’s pharmacy on Royal Street. It was then popularized at Sazerac Coffee House, a saloon on Exchange Place in the French Quarter. The drink and eventually its primary source were named for the brand of Cognac that favored the drink, Sazerac de Forge et Fils. The primary ingredient was switched to rye whiskey in 1870 due to imbibers’ changing tastes and an absinthe dash/rinse was added.

Who invented it: Apothecary Antoine Amédée Peychaud, who did indeed concoct Peychaud’s bitters, served friends a brandy cocktail spiked with his bitters.

What is it: Absinthe (or Herbsaint), rich simple syrup (sugar to water ratio, two to one), Peychaud’s Bitters, rye whiskey. It is New Orleans’ own cocktail in the truest historic definition. It actually bears more resemblance to what Jerry Thomas (considered the father of American mixology) referred to as an “improved” cocktail (an old term from the beginning on the cocktail, basically referring to an Old Fashioned with something added to it) with absinthe, but the Peychaud’s bitters makes it New Orleans’ own.

http://www.eater.com/2015/2/17/8053293/a-history-of-classic-cocktails-born-in-new-orleans