From that point onwards , his career focused on composition .
Altena also founded his own ensemble , the Maarten Altena Kwartet ( Maarten Altena Quartet ) which expanded into the Maarten Altena Ensemble ( MAE ) in 1980 .
From that point onwards , Altena 's career focused on composition .
Altena also founded his own ensemble , the Maarten Altena Kwartet ( Maarten Altena Quartet ) which expanded into the Maarten Altena Ensemble ( MAE ) in 1980 .