The first Mass in the Liber missarum IIII. V. VI. et VIII. vocibus (Antwerp, 1621) by the Portuguese composer Duarte Lobo (c. 1565-1646). The Agnus Dei is scored for five voices with a canon (Quinta vox per tempora sequitur me. Quatuor tacendo initio finem reperies) where the Altus sings only the Breves of the Superius.
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