Remy Martin is a brand of cognac. Cognac is a type of brandy that must contain specific types of grapes from a particular region of France. Cognac is also distilled twice and aged in oak barrels for at least two years, while brandy is only distilled once.
This results in cognac being richer and more complex in flavor than brandy. Louis XIII cognac is a premium cognac that is made with grapes from the Grande Champagne region of France. It is then aged for at least 100 years in oak barrels.