MANAHATTAN

Popular history ties the invention of the Manhattan to Sir Winston Churchill's mother and a fashionable (and political) dinner party she hosted at the Manhattan Club in New York City in 1874.  Although the claim is probably bogus (the date coincides with young Winston's christening), the trend to order the Manhattan Club Cocktail seems to have originated around this same time. 

The 1880's spawned other names for the drink as well, including Turf Club and Jockey Club cocktails.  A Broadway bar near Houston Street had introduced a similar cocktail in the 1860's, and in more modern times, this "drinking man's cocktail" regained popularity in Manhattan's jazz bars of the twenties and forties and as the preferred cocktail of Frank Sinatra and his infamous "rat pack."

Going back even further in time, an earlier instance places a medicinal version of the cocktail in Maryland in 1846, in the aftermath of a duel that had dire consequences.

MARGARITA

The Margarita, by contrast, appears to have been invented sometime between 1934 and 1948, probably in Mexico but maybe in Texas, elevating the previously ritual tequila to prominent cocktail status.

Claimants to the birth of the Margarita tended to name the drink after a particular woman--sometimes a friend or relative of the bartender or owner (in one instance, a wedding present for a soon-to-be sister-in-law) or in honor of a celebrity (Rita Hayworth, Peggy Lee . . .).

Hostess and bar-owner Margaret Sames, who offered how-to Margarita tips on television's Today show, introduced the coarse salt garnish which has become practically synonymic with today's Margarita.

MARTINI

A German ex-patriate and musical prodigy living in France in the later half of the eighteenth century adopted the pseudonym Jean Paul Aegide Martini--because Italian composers were all the rage.  The ruse served him well, bringing him popularity and success --among his works is a cantata written for Napoleon's wedding.  The name, in turn, became attached to his favorite drink--the French gen coupled with a dry white wine (could that have been Italian vermouth?).  After Martini's death, musicians continued to call for the cocktail by his name.

A century later, New York famed bartender and self-promoter Professor Jerry Thomas created the Martinez, a California cousin to the Martini, and is often credited with the Martini as well.  But Harry Johnson's 1882 bartender's manual most likely gave the Martini its first mention in print.

A johnny-come-lately, bartender Martini di Arma di Tagglia introduced John D. Rockefeller to the Martini at the Kninckerbocker Hotel in 1910.  The oil mogul liked the new drink, and a trend ensued.