After the death of Christopher Plantin, his profitable privileges were clustered into one general privilege which covered the liturgical editions and Bibles in several languages as well as several other categories of texts. It belonged to the manager of the Officina Plantiniana for the duration of his life. After the death of the holder his successor had to transfer the general privilege in his name as soon as possible. Their competitors in Antwerp did not respect the privilege of the Moretuses: they issued their own editions, in particular the Missale Romanum in folio, for which the Council of Brabant had granted them the required privilege. For that reason Balthasar Moretus I decided to have the general privilege renewed and confirmed. In autumn 1640 his homonymous nephew and future successor Balthasar Moretus II travelled twice to the Brussels court to lobby. This article reconstructs the activities of Balthasar the Younger and the Brussels network of the Moretuses using letters and other archival records. The court physician of the governor handed over the petition in person to his employer, and the chief president and the secretary of the Privy Council acted very loyally in support of the Moretuses’ case. When the advice of the archbishop of Mechelen and the bishop of Antwerp was asked, Balthasar Moretus II tried to win their support with objective arguments. He compared the Plantiniana edition of the missal in folio with the latest edition of his fiercest competitor Jan van Meurs. In this way he was able to put the higher price of the Officina Plantiniana into perspective. With great skill his allies in the Privy Council managed to obstruct the proposal of instituting a fixed book price. On 19 April 1641 the Privy Council confirmed the general privilege of the Officina Plantiniana. The Antwerp competitors complied and Balthasar Moretus II was able to focus the production of his presses on the lucrative liturgical market.