Celso Benigno Luigi Costantini (Chinese: 剛恆毅, 3 April 1876 – 17 October 1958) was an Italian Roman Catholic cardinal and the founder of the Disciples of the Lord who served as the head of the Apostolic Chancery from 1954 until his death.

He became the Titular Bishop of Hierapolis in 1921 and he received his episcopal consecration a month after from Cardinal Pietro La Fontaine with Angelo Bartolomasi and Luigi Paulini serving as the co-consecrators.

[1] Pope Pius XI appointed Costantini as the first Apostolic Delegate to China on 12 August 1922 and also made him Titular Archbishop of Theodosiopolis in Arcadia the following month.

He met with Pius XI before his departure and with Cardinal Willem Marinus van Rossum who advised Costantini to implement all dimensions of Maximum illud, Pope Benedict XV's 1919 apostolic letter on the work of missionaries.

He founded the Disciples of the Lord in 1928 with the help of the Spanish Redemptorist missionaries,[4] and he became the apostolic administrator for Harbin in 1931 though returned to his homeland at that time and then to the United States to recover from several health issues.

On 28 October 1926 he was present in the Sistine Chapel when Pius XI consecrated the first six Chinese bishops after he and the bishops-elect left from Shanghai on the previous 10 September.

Before his death, he told Cardinal Angelo Giuseppe Roncalli, soon to be elected pope, that he supported the candidacy of Gregorio Pietro Agagianian.

It opened under Pope Francis on 24 June 2016 after the Congregation for the Causes of Saints titled him as a Servant of God and transferred the forum of investigation from Rome to Concordia.