Osvald Sirén. "Some Early Italian Paintings in the Museum Collection." Museum of Fine Arts Bulletin 14 (April 1916), pp. 14–15, ill., assigns it to Filippo Lippi's middle period, dating it to about the time of the frescoes in the cathedral of Prato and tentatively identifying the two standing saints as Augustine and Francis; considers it the right wing of an altarpiece which may have had in its predella a scene of Saint Augustine's Vision of the Christ Child now in the Hermitage Museum, St. Petersburg, as well as the panels framed as the predella of the Annunciation in the church of San Lorenzo, Florence.
B[ryson]. B[urroughs]. "Four Saints by Fra Filippo Lippi." Metropolitan Museum of Art Bulletin 13 (November 1918), p. 232, ill. on cover, identifies the two kneeling saints as Louis and Benedict.
Raimond van Marle. The Development of the Italian Schools of Painting. Vol. 10, The Renaissance Painters of Florence in the 15th Century. The Hague, 1928, pp. 406–7, dates it in Lippi's early period, before 1437, and notes the influence of Fra Angelico.
[Georg] Gronau in Allgemeines Lexikon der bildenden Künstler. Ed. Hans Vollmer. Vol. 23, Leipzig, 1929, p. 273, lists it as by Lippi.
Lionello Venturi. Pitture italiane in America. Milan, 1931, unpaginated, pl. CLXXVIII, identifies the standing saints as Augustine and possibly Francis, those kneeling as Louis of Toulouse and Benedict; calls it the right wing of a triptych to which the Hermitage panel [see Ref. Sirén 1916] also belonged.
Bernhard Berenson. Italian Pictures of the Renaissance. Oxford, 1932, p. 288, lists it as by Lippi and calls it a fragment.
B[ernard]. Berenson. "Fra Angelico, Fra Filippo, e la cronologia." Bollettino d'arte 26 (August 1932), p. 52, says that it represents saints Francis and perhaps Jerome with two bishops; considers it contemporaneous with Lippi's Coronation in the Galleria degli Uffizi, Florence, here dated 1441.
Lionello Venturi. Italian Paintings in America. Vol. 2, Fifteenth Century Renaissance. New York, 1933, unpaginated, pl. 209.
Bernhard Berenson. Pitture italiane del rinascimento. Milan, 1936, p. 247, as an early work by Lippi.
Georg Pudelko. "Per la datazione delle opere di Fra Filippo Lippi." Rivista d'arte 18 (1936), p. 56 n. 1 no. 12, attributes it to a pupil of Lippi whom he names "Scolaro di Prato" and tentatively describes it as belonging to the same altarpiece as the Hermitage panel.
Harry B. Wehle. The Metropolitan Museum of Art: A Catalogue of Italian, Spanish, and Byzantine Paintings. New York, 1940, pp. 28–29, ill., dates it roughly 1437–43.
Robert Oertel. Fra Filippo Lippi. Vienna, 1942, p. 68, fig. 67, calls it a weak work by Lippi and dates about 1445.
Mary Pittaluga. Filippo Lippi. Florence, 1949, p. 209, fig. 153, attributes it to Lippi with the collaboration of Fra Diamante and dates towards the end of the 1450s.
Bernard Berenson. Italian Pictures of the Renaissance: Florentine School. London, 1963, vol. 1, p. 113, as an early, partly autograph work by Lippi.
Federico Zeri with the assistance of Elizabeth E. Gardner. Italian Paintings: A Catalogue of the Collection of The Metropolitan Museum of Art, Florentine School. New York, 1971, p. 92, ill., state that the conception and design are probably by Lippi, but the execution mostly the work of assistants; believe it probably dates to somewhere in the 1450s; note that the kneeling bishop saint lacks any attributes that would identify him as Louis of Toulouse.
Burton B. Fredericksen and Federico Zeri. Census of Pre-Nineteenth-Century Italian Paintings in North American Public Collections. Cambridge, Mass., 1972, pp. 106, 366, 375, 378, 397, 424, 606, attribute it to Filippo Lippi and identify the kneeling saint at left as Louis.
Giuseppe Marchini. Filippo Lippi. Milan, 1975, pp. 96–97, 204, no. 20, fig. 40, accepts the proposed connection with the predella panel in the Hermitage.
Miklós Boskovits in Opus Sacrum. Ed. Józef Grabski. Exh. cat., Royal Castle, Warsaw. Vienna, 1990, pp. 70–71 n. 20.
Nicholas H. J. Hall, ed. Colnaghi in America: A Survey to Commemorate the First Decade of Colnaghi New York. New York, 1992, p. 131.
Jeffrey Ruda. Fra Filippo Lippi: Life and Work, with a Complete Catalogue. London, 1993, pp. 409, 416–18, no. 33, pl. 254 (during cleaning), states that it may have been painted largely by Lippi in the early or mid-1440s, noting that none of the saints is clearly identified and calling them "St Francis(?), St. Benedict(?) and two Bishop Saints".
Keith Christiansen in From Filippo Lippi to Piero della Francesca: Fra Carnevale and the Making of a Renaissance Master. Ed. Keith Christiansen. Exh. cat., The Metropolitan Museum of Art. New York, 2005, p. 64 n. 44 [Italian ed., "Fra Carnevale: un artista rinascimentale da Filippo Lippi a Piero della Francesca," Milan, 2004, p. 64 n. 44].