Eberhard Billick was a German theologian instrumental in keeping the city of Cologne Catholic during the Reformation.
Billick's activity on behalf of his order was successful; he enrolled numerous candidates, improved the plan of studies, saved several monasteries from destruction, re-established others, and reformed both his own province and that of Upper Germany.
If Cologne remained true to the Catholic cause the merit is principally due to the provincial of the Carmelites.
As the leader of the lower clergy he protested against the heretical tendencies of Archbishop Hermann von Wied, who since 1536 had favoured the Reformers.
He took part in the disputations of Worms, 1540, Ratisbon, 1541 and 1546, and Augsburg, 1547, and as theologian accompanied the new Archbishop of Cologne to the Council of Trent, 1551.