The religious habit of Roman Catholic sisters sometimes consists of a plain dress and a veil. Different orders adhere to different styles of dress; these styles have changed over time. For example, in former times, the Daughters of Charity of Saint Vincent de Paul wore a cornette instead of a veil. Some congegrations decided in the course of changes due the ecclesiatical document "Perfectae caritatis" to simplify their habits, to conform to the attire of the culture they are working in, or to even drop their use at all.