In the Catholic Church, a quinquennial visit ad limina, more fully ad limina apostolorum or simply an ad limina visit, means the obligation of residential diocesan bishops and certain prelates with territorial jurisdiction (such as territorial abbots), of visiting the thresholds of the [tombs of the] Apostles, Saints Peter and Paul, and of meeting the pope to report on the state of their dioceses or prelatures. It is a formal trip usually made together by all bishops from a single region (viz., an episcopal conference) to discuss with the Pope issues specific to their regions. It is separate from other trips a bishop might make to the Vatican, such as to attend a synod. The ad limina visit happens every five years, or quinquennially.
Limina is the accusative plural of the Latin language noun limen, meaning literally "a threshold; the head-piece or foot-piece of a doorway," and in a transferred sense, "a house, dwelling, abode." The Latin preposition ad means "to, toward, at."
In 1585 Pope Sixtus V[inconsistent] issued the constitution Romanus Pontifex[inconsistent], which set forth the norm for visits ad limina. On December 31, 1909, Pope Pius X stated in a Decree for the Consistorial Congregation that a bishop needs to deliver an account of the state of his diocese to the pope once every five years, starting in 1911.