Grand Marnier (also called Grand Marnier Cordon Rouge for the red ribbon around the neck) is a brand of orange liqueur made by the Lapostolle family since 1870, but the story of Grand Marnier goes back further, to 1827.
It was in 1827 when Jean-Baptiste Lapostolle opened a small distillery near Paris. He needed knowledge of distilling, so he travelled to the Cognac region to learn the trade, eventually bringing back stocks of Cognac to age in his cellars.
In 1870, the grand-nephew of Jean-Baptiste, Louis-Alexandre Marnier-Lapostolle invented a liqueur that blended an alcohol extraction of Bigarade oranges from the Caribbean, Cognac, and sugar syrup, and called it Grand Marnier. It became a popular part of French cooking -- Escoffier used it to make Crepes Suzette.
Grand Marnier is still made from the original 1870 recipe. To integrate the flavors, the liqueur rests for 6-8 months in barrel before being bottled.
Grand Marnier is a warm amber-gold color and clear. The aroma and flavor is strongly orangey, but it's more of a perfume orange than a natural orange aroma. There are notes of honey and a base of woody Cognac. Grand Marnier is 80 proof.
While Grand Marnier is not quite suited for substitution with the neutral spirit branch of orange liqueurs, cocktails that have brandy or Cognac as a component can handle the switch.
The Lapostolle family makes a few other liqueurs of note: Cordon Jaune (yellow ribbon) that is neutral spirit based and a substitute for Cointreau, two specialty cuvees (a 100th anniversary and a 150th anniversary that should be sipped neat), Navan, a vanilla and Cognac liqueur, and Cherry Marnier, made from morello cherries. Neither Cordon Jaune nor Cherry Marnier are currently imported into the United States.