The ship taking Convolvulus to Rome never made it.Convolvulus' discord-sowing went horribly right, and in the ensuing chaos the ship was either damaged or caught in a storm, and went down with all hands, including Convolvulus.
Dubbelosix's specialty was a life-prolongation/eternal youth potion.Unfortunately, it only works on houseflies.
The brew they drink regularly for strength in battle may have basis in truth.
Getafix secretly wants the Gauls to be part of Roman EmpireNote also that both Gauls and the Romans use the normal font, and Asterix and Obelix never have any problems with understanding Romans. They speak Latin. It reaches its peak when they outright admit in the Olympic Games that they're Romans. They benefit from a lot of Roman infrastructure (roads, bridges, entertainment). Many Gauls claim that Ceasar is actually the greatest leader of their age - see the Laurel Wreath for instance. The only reason why Getafix uses the magic potion is to keep Cesar in check.
Astérix and Son was going to be the series finale.You can't get any more closure than Caesar and the Gauls sharing the banquet.
The finale will be Astérix and the Ides of March.Getafix is the soothsayer.
Asterix and Tintin take place in the same universe.More specifically, Asterix, Obelix, Getafix, Dogmatix and Cacofonix are the ancestors of Tintin, Haddock, Calculus, Snowy and Castafiore. Also, the Thompsons appearing in "Asterix in Belgium" are the ancestors of the real Thompsons. Both universes contain aliens, which strengthens the theory, and Asterix appears at a parade in "Tintin and the Picaros". This is someone in a large Asterix costume... but it could be the real Asterix immortalized by magic potion...
Several Gallic druids know the recipe to the magic potion.As Getafix has stated, druids can only trust each other with their magic recipes. So why hasn't he given the magic potion recipe to all of his colleagues? The answer is: He has, or at least he has offered to. But they choose not to make it, because the majority of Gaul's population are satisfied with the Romans' rule. This has been confirmed in several stories. They have no interest in starting a new war to get rid of the Romans.
Asterix is set in an Alternate History where Julius Caesar was never assassinated.Hence why he and Obelix can have so many adventures in such a seemingly short space of time.