Christian religious orders established in the 15th century

Roman Catholic religious order of friars

The Alexians, or Cellites, officially named as the Congregation of Alexian Brothers (), abbreviated C.F.A., is a Catholic lay religious congregation of Pontifical Right for men, specifically devoted to caring for the sick. The congrgation has its origin in Europe at the time of the Black Death. Its members follow the Rule of Saint Augustine.

The Order of the Immaculate Conception (), abbreviated OIC and also known as the Conceptionists, is a Catholic religious order of Pontifical Right for nuns founded by Saint Beatrice of Silva. For some years, they followed the Poor Clares Rule, but in 1511 they were recognized as a separate religious order, taking a new rule with the name Order of the Immaculate Conception. (In some areas they are still known as the Franciscan Sisters of the Immaculate Conception.)

Third Order of Our Lady of Mount Carmel

Roman Catholic religious congregation for women