The Book of Pastoral Rule (Latin: Liber Regulae Pastoralis, Regula Pastoralis or Cura Pastoralis — sometimes translated into English Pastoral Care) is a treatise on the responsibilities of the clergy written by Pope Gregory I around the year 590, shortly after his papal inauguration. It became one of the most influential works on the topic ever written. The title was that used by Gregory when sending a copy to his friend Leander of Seville.