Guild of Saint Luke
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.