And here is the sweet vermouth version, created 4 years after the dry vermouth version. Byrrh Cocktail (Jacques Straub, 1914) with Byrrh grand quinquina, Martini Gran Lusso vermouth, Michter's straight rye.
The Savoy Cocktail book has its own variation of this as well (Byrrh, sweet vermouth and Canadian Club whisky, in equal parts).