So apparently Collaborative Strategies were big in Antwerp around the 16th & 17th centuries... I saw this painting "Battle of Amazons" a collaborative painting by Jan Bruegel and P.P. Rubens at the Rubenhuis, in downtown Antwerp.
Earlier this morning I came accross another Bruegel collaboration, a painting of the 9 muses meeting with Minerva, the Roman Goddess of War. This painting, which I didn't get then name of, was housed in the Koninklijk Museum voor Schone Kunsten Antwerpen.