What is the fine-grained topic of the following text: lengthy thought of a minor grasp overshadowed via such figures as his instructor Jan Pieterszoon Sweelinck or his fellow scholar Samuel Scheidt, a couple of significant resource discoveries made within the moment half the 20 th century - crucial one being the invention of the Zellerfield tablatures - have steadily raised his stature in the direction of what it may now be, particularly that of the paramount determine in North German organ song of the 1st half the 17th century, equalled basically by way of Buxtehude within the moment part. Only return the topic.
The prominence and relevance of a figure in North German organ music of the 17th century due to recent tablature discoveries.