The final film, made in 1998, was written by Bahs alone.

The Olsen Gang was one of Nordic Film’s biggest successes in modern times, both in Denmark and abroad. It was also a major success for the three main stars: Ove Sprogøe who played the gang leader Egon Olsen and Morten Grunwald and Poul Bundgaard who played his two suburban hangers-on Benny and Kjeld.

Almost all of the films start with Egon being released from prison with a plan under his arm - and the plan always involves stealing millions from big business! Egon does it to prove that he can pull off the job of the century, Benny because he wants to prove that he is as smart as he thinks he is and Kjeld joins in all the fun and games to escape from his wife Yvonne (played by Kirsten Walther) who is for ever pestering him for money for confirmations, silver weddings, consumer goods and whatever else has caught her fancy.

Erik Balling and Henning Bahs travelled to Paris to think up and write new manuscripts for the Olsen Gang films.

They would take rooms at Hotel Proust in Rue des Martyrs at the foot of Montmartre - always rooms 28 and 32 on the fifth floor, facing the yard and nice and quiet.

Equipped with a typewriter each and a lot of notes and ideas on squared paper, the creative process could begin. And it always started with the same questions: "How's Yvonne?" and "What is Yvonne preoccupied with now?" All of Messrs. Balling and Bahs’ fantastic ideas, which enriched Danish life for many years, flowed from that same starting point.

The musical theme for the films was written by Bent Fabricius-Bjerre and Danes of all ages still whistle or hum along to it.

Some of the more prominent bit parts in the series included Ove Verner Hansen as Muscles, Jes Holtsø as Børge, Preben Kaas as Dynamite Harry, Axel Strøby and Ole Ernst as detectives Jensen and Holm and Bjørn Watt Boolsen as the head bad guy who appeared under the names Hallandsen, Bang-Johansen, Holm-Hansen and the Baron.