While crossing the great Coal Forest, Charlemagne stops in a clearing. A jay flies by and drops an acorn that hits the emperor's skull. With his foot, Charlemagne pushes it into the ground. He adds: little acorn, the inhabitants of Liernu will remember you. This oak is more than 1000 years old. Its trunk was transformed into a chapel dedicated to Saint Antony the Hermit. On 30 May 2015 three twinned oaks inspired by the concept of the "father of Europe" founded in Liernu the Chain of the European Oaks.