The hymn recalls the burden of work and the heat of the day to pray for the peace of the soul amid the dangers of struggle and passion. Ancient writers (Hippolytus, Constit. Apost.) place the Lord’s Crucifixion precisely at that hour of the day. The S. has the same origin and structure as the other minor hours of the day, Terza and Nona (q.v.).
BIBL.: H. Leclercq, Sette et Tierce, in DACL, XV, 1, cols. 1390-99. C. Callewaert, De Brev. rom. liturgia, Bruges 1939, nn. 212, 226, 317, 318; P. Albrigi, Sacra liturg. L'ora pubblica, Vicenza 1942, pp. 88-90, 439-441; M. Righetti, Man. di stor. litur., Milano 1946, pp. 421-23, 584-86. Pietro Siffrin