Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
JANSSEN
As described in historical dictionaries
Patronymica Britannica (1860)
JANSSEN. Originally from G uelderland. The head of the family was the Baron de Heez, one of the Protestant leaders against the Inquisition andthe tyranny of the Duke of Alva; he unfortunately fell into the hands of the Duke of Parma, and lost his estate and his life. On the dispersion of his family, his youngest son took refuge in France, and settled at Angouleme, where he lived to a very advanced age, leaving "a great estate and a numerous issue." His grandson, Theodore Janssen, removed into England in 1680, and was subsequently created a baronet by George I.
Region of origin: Europe
Country of origin: Germany
Language of origin: German