The praeludium pedaliter on folio 36 of manuscript Lynar B3 bears the initials M.F.P.S.W. Or M.J.P.S.W. Both readings of the second initial are possible. It seems common agreement that these initials signify "Magister Johan Pieterszoon Sweelinck". Well, who am I do disagree. Perhaps there are other sources that attribute this composition unambigiously to Sweelinck. Based on Ms Lynar B3 alone, the attribution seems a bit thin.
The prelude itself is a largely homophonic composition, that bears little resemblance to other compositions by Sweelinck. A nice piece to play, just not very impressive.