The imperial ban (German: Reichsacht) was a form of outlawry in the Holy Roman Empire.
[2] People under imperial ban, known as Geächtete (from about the 17th century, colloquially also as Vogelfreie, lit.
The Aberacht, a stronger version of the imperial ban, could not be reversed.
The effect of the ban on a city or other Estate was that it lost its Imperial immediacy and in the future would have a second overlord in addition to the emperor.
Famous people placed under the imperial ban included: The imperial ban imposed by the Emperor Rudolf II on the city of Donauwörth after an anti-Catholic riot was one of the incidents leading to the Thirty Years' War.