[1] Then, in 1414, Lyndwood was appointed "Official" of the Archbishop of Canterbury (i.e. his principal adviser and representative in matters of ecclesiastical law) in 1414, and Dean of the Arches in 1426, while holding at the same time several important benefices and prebends.

In 1433, he was collated Archdeacon of Stow in the Diocese of Lincoln, and in 1442, after an earnest recommendation from King Henry VI, he was promoted by Pope Eugene IV to the vacant See of St. David's.

[3] Lyndwood, however, is chiefly remembered for his great commentary upon the ecclesiastical decrees enacted in English provincial councils under the presidency of the Archbishops of Canterbury.

This elaborate work, commonly known as the Provinciale, follows the arrangement of the titles of the Decretals of Gregory IX in the Corpus Juris, and copies of much of the medieval English legislation enacted, in view of special needs and local conditions, to supplement the jus commune.

[3] It should be read together with John of Acton's gloss, composed circa 1333–1335, on the Legatine Constitutions of the thirteenth century papal legates, Cardinals Otto and Ottobuono for England, which was published with the Provinciale by Wynkyn de Worde.