Asterix Versus Caesar is the first of the 1980s Asterix films and the fourth film adaptation based on the Asterix comic books. It was released in 1985. The plot was adapted primarily from the books Asterix the Legionary and Asterix the Gladiator by Goscinny and Uderzo's friend Pierre Tchernia. The film's theme song Astérix est là was composed and performed by Plastic Bertrand.