His father was a wealthy goldsmith, jeweller, and engraver who had fled persecution in Brussels.
A year later, Johann Israel de Bry (1565–1609) married Jennis’ widowed mother.
Jennis was now a member of the de Bry family, who were famous for their engraving work.
His work was an influential aspect of seventeenth century alchemy, which saw the printing of an unprecedented number of alchemical texts.
His copperplate engravings were used in the production of Hermetic emblems, used to convey the symbolic ideas in alchemy pictorially.