Ildefonso, whose name is more familiar in its Castilian form, Alfonso, was appointed archbishop of Toledo in 657 and later became that city's patron saint. He was especially famed for his book defending the purity of the Virgin, which he was said to have written at her dictation.
El Greco represented the saint in a richly decorated room, seated at a writing table furnished with costly silver desk ornaments consistent with the style of the artist's own time. The contemporary setting notwithstanding, an otherworldly aura pervades the room as the saint pauses in his writing and, as though awaiting the next word, gazes attentively at the source of his inspiration, a statuette of the Madonna. The combination of strangely compacted space, the chalky highlights that play over the saint's sleeves and the velvet tablecover, and, not least, Ildefonso's fervent expression, remove the scene to a spiritual realm.
El Greco's image of the Virgin resembles an actual wooden figure that Ildefonso is said to have kept in his oratory until it was given by him to the church of the Hospital of Charity in the small Spanish town of Illescas, near Toledo. The statuette is preserved there today together with El Greco's larger version of Saint Ildefonso.
More information on this painting can be found in the Gallery publication Spanish Paintings of the Fifteenth through Nineteenth Centuries, which is available as a free PDF https://www.nga.gov/content/dam/ngaweb/research/publications/pdfs/spanish-painting-15th-19th-centuries.pdf
lower left: (traces of a signature in cursive Greek)
Probably in the artist's possession at the time of his death in 1614; his son, Jorge Manuel Theotocópuli, Toledo, by 1621. Presented 1698 to Carlos II [1661-1700] by Don Juan Varela Colima, the King's secretary and tax collector for the city and province of Toledo. Condesa de Quinto, Paris; (sale, Paris, 1862, no. 64, as Un saint Évêque écrivant, les regards tournés vers l'image de la Sainte Vierge); Alphonse Oudry; (his sale, Hôtel Drouot, Paris, 16-17 April 1869, no. 139, as Prélat écrivant l'histoire de la Vierge, for 500 francs); Jean-François Millet [1814-1875], Paris; his widow, Catherine Lemaîre Millet; (her estate sale, Hôtel Drouot, Paris, 24-25 April 1894, no. 261, as L'Évêque, for 2000 francs); acquired by (Durand-Ruel, Paris) for Hilaire-Germain-Edgar Degas [1834-1917], Paris;  (his atelier sale, Galerie Georges Petit, Paris, 26-27 March 1918, 2nd day, no. 2, as Saint Ildefonso écrivant sous la dictée de la Vierge); (M. Knoedler & Co., London and New York); sold 7 February 1922 to Andrew W. Mellon, Pittsburgh and Washington, D.C.; deeded December 1934 to The A.W. Mellon Educational and Charitable Trust, Pittsburgh; gift 1937 to NGA.
- Paintings by Old Masters from Pittsburgh Collections, Carnegie Institute, Pittsburgh, 1925, no. 21.
- Spanish Paintings from El Greco to Goya, The Metropolitan Museum of Art, New York, 1928, no. 31.
- A Century of Progress Exhibition of Paintings and Sculpture, The Art Institute of Chicago, 1933, no. 175.
- Paintings and Sculpture Owned in Washington, Phillips Gallery, Washington, 1937, no. 13.
- El Greco of Toledo, The Toledo [Ohio] Museum of Art; Prado, Madrid; National Gallery of Art, Washington; Dallas Museum of Fine Arts, 1982-1983, no. 43, pl. 56.
- The Private Collection of Edgar Degas, The Metropolitan Museum of Art, New York, 1997-1998, no. 599, repro.
- El Greco in the National Gallery of Art and Washington-Area Collections: A 400th Anniversary Celebration, National Gallery of Art, Washington, 2014-2015, no catalogue.
- Tillot, Charles S. Catalogue de la vente qui aura lieu par suite de décès de Jean-François Millet, peintre. Hôtel Drouot, Paris, 10-11 May, 1875: ix.
- Lafond, Paul. "Domenikos Theotokopuli dit Le Greco." Les arts 58 (1906): 25-26.
- Cossío, Manuel B. El Greco. Madrid, 1908: 334, 598-599, no. 299 (also rev. ed., ed. Natalia Cossío Jímenez. Barcelona, 1972: 194, 383, no. 255).
- Mayer, August L. El Greco. Munich, 1911: 83.
- Frappart, A. "Chronique des ventes." Les arts 168 (1918): 26.
- Field, Hamilton Easter. Editorial. The Arts 1 (1920): 6, repro. 7.
- Mayer, August L. Domenico Theotocopuli, El Greco. Munich, 1926: 46, no. 287, pl. 63.
- Burroughs, Bryson. "Spanish Paintings from El Greco to Goya." Bulletin of The Metropolitan Museum of Art 23 (1928): 39, repro. 40.
- Rutter, Frank. El Greco. New York, 1930: 96, no. 67.
- Holmes, Sir Charles J. Self & Partners (Mostly Self). London, 1936: 340.
- Cortissoz, Royal. An Introduction to the Mellon Collection. Boston, 1937: 42-43.
- Legendre, Maurice and Alfred Hartmann. Domenikos Theotokopoulos Called El Greco. Paris, 1937: 433, repro.
- Goldscheider, Ludwig. El Greco. London, 1938: pl. 181 (also 1954 rev. ed.: pl. 187).
- Preliminary Catalogue of Paintings and Sculpture. National Gallery of Art, Washington, 1941: 92, no. 83.
- Book of Illustrations. National Gallery of Art, Washington, 1942: 240, repro. 215.
- Cook 1945, 73-74, fig. 5.
- Paintings and Sculpture from the Mellon Collection. National Gallery of Art, Washington, 1949 (reprinted 1953 and 1958): xii, repro.
- Gaya Nuño, Juan Anotonio. La pintura española fuera de España; historia y catàlogo. Madrid, 1958: 206, no. 1397.
- Evans, Grose. Spanish Painting in the National Gallery of Art. Washington, D.C., 1960 (Booklet Number Ten in Ten Schools of Painting in the National Gallery of Art, Washington, D.C.): 18, color repro.
- The National Gallery of Art and Its Collections. Foreword by Perry B. Cott and notes by Otto Stelzer. National Gallery of Art, Washington (undated, 1960s): 20.
- Wethey, Harold E. El Greco and His School. 2 vols. Princeton, 1962: 1:fig. 113; 2:19 (under no. 23), 239, no. X-361. (also Spanish ed. 2 vols., Madrid, 1967: 1:pl. 117; 2:34 [under no. 23], 254-255, no. X-361).
- Walker, John. National Gallery of Art, Washington, D.C. New York, 1963 (reprinted 1964 in French, German, and Spanish): 309, repro.
- Summary Catalogue of European Paintings and Sculpture. National Gallery of Art, Washington, 1965: 62.
- European Paintings and Sculpture, Illustrations. National Gallery of Art, Washington, 1968: 54, repro.
- Manzini, Gianna, and Tiziana Frati. L'opera completa del Greco. Milan, 1969: no. 125e.
- European Paintings: An Illustrated Summary Catalogue. National Gallery of Art, Washington, 1975: 162, repro.
- Walker, John. National Gallery of Art, Washington. Rev. ed. New York, 1984: 237, no 302, color repro.
- European Paintings: An Illustrated Catalogue. National Gallery of Art, Washington, 1985: 186, repro.
- Brown, Jonathan, and Richard G. Mann. Spanish Paintings of the Fifteenth through Nineteenth Centuries. The Collections of the National Gallery of Art Systematic Catalogue. Washington, D.C., 1990: 43-47, color repro. 45.
- Kopper, Philip. America's National Gallery of Art: A Gift to the Nation. New York, 1991: 67, color repro.
- National Gallery of Art. National Gallery of Art, Washington. New York, 1992: 81, repro.
- Griswold, Susanna P. "Two Paintings by El Greco: Saint Martin and the Beggar." Studies in the History of Art 41 (1993): 133, 142, 148, repro. no. 3.
- Ives, Colta et al. The Private Collection of Edgar Degas: A Summary Catalogue. New York, 1997: no. 599.
The original support is a coarse, plain-weave fabric. Before 1937 the tacking edges were flattened, and the picture was lined to a larger, medium-weight, plain-weave fabric. The white ground layer and the dark red imprimatura do not conceal the weave texture. X-radiographs reveal that the ground layer is applied roughly; striations indicate that the artist may have used a palette knife or small trowel. The imprimatura was left exposed in several places, notably along the edges of the saint's left arm and hands. The paint was applied in a moderately thick, textured paste with translucent layers in the table covering and the Madonna's robe. The original right and left tacking margins are covered by daubs of paint; those on the right were left exposed after the recent treatment. Small areas of loss are scattered throughout, but significant losses of paint are confined to the edges of the original picture surface. The painting was cleaned and treated in 1988.
 Pigment analysis in September 1987 detected lead white, iron oxide, and possibly red lead in the red table covering. X-ray fluorescence cannot detect the crimson lake dyes assumed to have been used in the glaze. Red lake pigment, which gives a purplish hue, was mixed with lead white and azurite in the blue robe of the saint, which may also contain blue verditer and ultramarine. The yellow highlights of the hem of the Madonna's robe are probably lead-tin yellow, mixed with yellow ochre and possibly massicot. On El Greco's blue pigments, see Susanna Pauli, "Two Paintings by El Greco: Saint Martin and the Beggar. Analysis and Comparison" (forthcoming publication, conservation department papers, National Gallery of Art).