A lemmatic commentary on Quadripartitum III.10, dealing with the directions and the length of life, in Plato of Tivoli’s translation (A.1.2). This commentary is extant as a continuous and stand-alone text in a single manuscript (Oxford, BL, Digby 57), but it also occurs, in part or in full, as marginal glosses in nine copies of the Quadripartitum in Plato’s translation (Brussels, BR, 18678-18681, f. 82r-85r; Cambrai, BM, 955 (853), f. 92v-99v; Cesena, BCM, Plut. S.XXVII.3, f. 82r-84r; Paris, BnF, lat. 7302, f. 51v-62v (where the glosses have been inserted into the text); Pommersfelden, GSB, 60 (2633), f. 78r-88v; Salamanca, BU, 2051, f. 48r-49v; Vatican, BAV, Pal. lat. 1420, f. 20v-22v; Vatican, BAV, Reg. lat. 1285, f. 123r-126r; and Vatican, BAV, Vat. lat. 7616, f. 26r-29v). The text is anonymous, but the opening ‘Sensus huius litere’, as well as the style and modus operandi of the exposition are distinctive of Gerard of Cremona’s commentaries. The nine above-mentioned manuscripts contain many more glosses, also clearly by Gerard of Cremona, which cover altogether most of the Quadripartitum, but it is unclear whether Gerard produced a continuous and stand-alone commentary on the complete text, as he did for the Almagest (C.1.3). The same kind of glosses also occur in several manuscripts of Abuiafar Hamet filii Joseph’s Commentum in Centiloquium in Plato of Tivoli’s translation (see C.3.1.1, Note 5). Gerard knew and used ʿAlī ibn Riḍwān’s commentary on the Tetrabiblos (see C.2.2), which he probably accessed through the Arabic, cf. Oxford, BL, Digby 57, f. 165v (‘Dicit Haly quod isti male faciunt…’), 166v (‘Et hoc idem voluit Haly qui hunc locum exposuit…’ and ‘Dicit Haly quod ex hiis verbis habetur quod direction…’) and 167r (‘Dicit Haly quod ideo Ptholomeus dimisit sextilem aspectum…’ and ‘Dicit Haly quod si latitudo unius fuerit septentrionalis…’).