The Walking Nuns Who Went to a War

Catherine McAuley built her congregation directly out of practical, active charity rather than convent life: the House of Mercy she opened in Dublin in 1827, four years before the community's formal establishment in 1831, sheltered and educated poor women and girls, and the sisters who followed her insisted on an active vocation that kept them moving through the city's streets to visit the sick and the poor, earning them the popular nickname of walking nuns among religious orders more accustomed to enclosure. That active, mobile character let the Sisters of Mercy respond to a very different kind of need barely two decades after the order's founding: during the Crimean War in the 1850s, Mercy sisters served as nurses alongside Florence Nightingale's better known mission, one of the earliest instances of Catholic religious women serving in an organised military medical capacity in a European conflict.

The congregation's combination of active nursing, teaching and social service, backed by its distinctive fourth vow of service to the poor, sick and uneducated, let it expand with unusual speed from a single Dublin house to communities across Ireland, England, the United States and Australia within a few decades of its founding.