H. C. Robbins-Landon edition (Latin text)

Mozart began composing this Mass in 1782. He was betrothed to Constanze Weber at the time; she had fallen gravely ill, and he had made a vow to write a Grand Mass for her recovery. Further, the plan was for Constanze to sing the aria Et incarnatus est (which was to be the centerpiece of the work) at the premiere performance. The Mass was a huge underaking. Before Mozart could complete it, Constanze recovered, their marriage went forward, and Mozart left the Mass unfinished (since he had vowed to write the work entirely on his own inspiration, there was no commissioner, hence no income to be garnered from it, hence no overwhelming compulsion to complete it. It is to be noted, of course, that Mozrt did complete Constanze's great solo, the aria Et incarnatus est, but never continued to write a single additional number for the Credo. He also never composed the final movement of the Mass, Agnus Dei - Dona nobis pacem