The root of this music is organ toccatas and fantasias, particularly derived from those of Claudio Merulo (1533–1604), organist at St Mark's Basilica in Venice.
A later practitioner in Rome was Girolamo Frescobaldi, and his German student Froberger took the style north with him.
The author, scientist and inventor, a true baroque polymath, Athanasius Kircher describes the stylus fantasticus in his book, Musurgia Universalis: The style is related to improvisation but is characterised by the use of short contrasting episodes and a free form, just like a classical fantasia.
Johann Mattheson, who was a German composer and theorist in the 17th century, presented his idea about the definition that Athanasius Kircher in his book, "Das beschutzte Orchestre" (1717), cited in Paul Collin's writing: Later in Mattheson's Der vollkommene Capellmeister (1739), he stated that the stylus fantasticus is more of a performance style than a composition approach.
In the Southern Netherlands, Nicolaus à Kempis pioneered the style in his Symphoniae published between 1644 and 1649 in Antwerp.