Nicolas Steno

Niels Steensen was born in Copenhagen on 1 January 1638 to a Lutheran family and trained in classical science, but by 1659 he'd begun tearing down received wisdom on tear ducts, fossils, and rock layers. His work on fossils and strata made him a founder of modern geology — so much so that a 2009 scholarly volume on the field's revolution devoted half its papers to him alone. In 1667 he converted to Catholicism, and his interest in natural science collapsed almost overnight, overtaken by theology. He was ordained a priest on Easter Sunday 1675, four months after deciding on the priesthood, then…