Bull Laetentur caeli, 6 July 1439, Denzinger nos. 691-692

In the name of the Holy Trinity, of the Father and of the Son and of the Holy Spirit, with the approval of this sacred universal Council of Florence we define that this truth of faith be believed and accepted by all Christians, and that all so profess it: that the Holy Spirit is eternally from the Father and the Son, and has his essence and his subsistent being from the Father together with the Son, and proceeds from both eternally as from one principle and by a single spiration; declaring that what the holy Doctors and Fathers say — that the Holy Spirit proceeds from the Father through the Son — tends to this understanding, that by it is signified that the Son too is, according to the Greeks the cause, and according to the Latins the principle, of the subsistence of the Holy Spirit, as is the Father. And since all that is the Father's, the Father himself in begetting gave to his only-begotten Son, save being Father, this very thing — that the Holy Spirit proceeds from the Son — the Son himself has eternally from the Father, by whom he was likewise eternally begotten. We define besides that the explanation of those words "Filioque" was lawfully and reasonably added to the Symbol for the sake of declaring the truth, and under the necessity then pressing.

Likewise, that the body of Christ is truly confected in unleavened or in leavened wheaten bread, and that priests ought to confect the body of the Lord in either one of these, each according to the custom of his own Church, whether western or eastern.