The Hugo Ensslin 1916 is the earliest known recipe and it is shaken with orange and lemon peels for added citrus brightness. Plus garnished with an orange twist. It was named for the turn of the century boxer David Deshler,
The recipe link lists the rye and Dubonnet as 1/2 jigger, isn't that 1 oz each, not 1.5 oz? FWIW, the Martin's Index app shows those as 1 oz with the rest of the ingredient proportions the same (and also notes that this is one of the earliest recipes that specified Cointreau by brand). I get it, that's a pretty small drink by today's standards, but the other ingredients should probably be scaled up as well with an extra dash (or a range of 2-3 dashes).