He studied for a few months under Justus Lipsius, but then fell sick and returned home to work in the office.
When he was the head of the Officina, he continued ordering illustrations from the workshop of engraver Theodore Galle.
Many of those are still preserved in the Plantin-Moretus Museum, and include portraits of Christoffel Plantin, Jan I Moretus and Justus Lipsius.
[3] Balthasar I Moretus was also responsible for the expansion and completion of the buildings of the company, which now are the Plantin-Moretus Museum.
This is a very partial list of the works published during the years that Balthasar I Moretus was leading the Plantin company.