Lumen Gentium, Dogmatic Constitution on the Church

Lumen Gentium is the Second Vatican Council's own Dogmatic Constitution on the Church, promulgated in 1964, cited here from the Vatican's own official published text of the document. As a primary institutional statement from the body that issued it, on the specific question of collegiality and the nature of the Church, it is the strongest possible source for what the Catholic Church's own council actually declared, in its own official wording, not a secondhand summary or later paraphrase of the teaching. Its limit is what any council document's own text necessarily is, an authoritative statement of doctrine rather than a historical or theological analysis of how that doctrine was debated, drafted or received, so a claim about the Council's internal debates or Lumen Gentium's later theological interpretation needs a scholarly historical source alongside this primary text.