Translate the following English sentence to French:
"During this time he has combined steadfastness with flexibility and intelligence to achieve a result which is acceptable to all the institutions and which will serve to make our seas cleaner."
Pendant tout ce temps, il a été capable d'allier fermeté, flexibilité et intelligence pour obtenir un résultat acceptable pour toutes les institutions et qui servira à améliorer la propreté de nos mers.