A young student, Frederic Ozanam had to walk through the poorer suburbs on his way to university lectures each day and he soon became deeply moved at the hopeless state of families who had been left without the support of their breadwinners after [a cholera] epidemic [had] swept through Paris killing up to 1200 people each day.

It was the taunt of an anti-religious opponent in a debating society founded by the students that stung him to action…