Gallus, Carolus (or Karel de Haan) (16 August 1530 in Arnhem – 28 January 1616 in Nijbroek) was a Reformed minister and polemicist against the Anabaptists.
Native to the Netherlands, Gallus was raised in a Roman Catholic family, and studied law and theology to become a priest.
He published his first book against the Anabaptists entitled Lehre de Christelicken geloovens in veer boecken tegen den wedertöpern erdömmen (Bremen, 1577 ?).
From 1578 to 1581, at the behest of Count Johan Nassau, he was a military chaplain with his friend Johannes Fontanus in Gelderland, where the Reformation was beginning to take hold.
He was appointed as professor of theology at the University of Leiden in 1587 and maintained this position rather shortly, as he took a call to become minister in Oldenbroek in 1592, where he remained until his death.