Lukasgilde
The only documentary evidence relating to Grimmer's training is his registration in 1539 under the name Iaques Grimmaer in the liggeren of the Antwerp Guild of Saint Luke as a student of Gabriel Bouwens. It is therefore not certain that Grimmer in fact was a pupil of Matthys Cock and Christian van den Queborn. Grimmer became a master in the Antwerp Guild of Saint Luke in 1547.