If Sweelinck indeed studied in Haarlem, he was probably influenced to some degree by the organists of St.-Bavokerk, Claas Albrechtszoon van Wieringen and Floris van Adrichem, both of whom improvised daily in the Bavokerk.
Hvis Sweelinck faktisk studerede i Haarlem, var han sandsynligvis påvirket af organisterne i Sankt Bavokerk, Claas Albrechtszoon van Wieringen og Floris van Adrichem, som begge improviserede dagligt i Bavokerk.