In the Duomo of Ferrara, there is a large altarpiece by Guercino (310 5 200 cm) which portrays the Martyrdom of St Lawrence, dated 1628. A whole series of statements have been made about this work, but in fact have absolutely nothing to do with it. Malvasia (1678, II, p. 367) mentions a “Tavola di un S. Lorenzo sopra la craticola per l’ Eminentiss.mo Magalotti da riporre in una sua cappella a Roma” (“Painting of St Lawrence above the grid for His Eminence Magalotti, to be placed in one of his chapels in Rome”). In modern literature about Guercino (which is summarised in the entry on the Ferrara painting in the catalogue of the Il Guercino exhibition, Bologna - Cento 1991, ed. Denis Mahon, no. 70, p. 198), it is taken for granted that this quotation refers to the Ferrara altar painting. Malvasia mentions this painting of St Lawrence in 1629, which means that a double error has been made by linking the Ferrara altarpiece to those statements, and then by dating it 1628. But, as Denis Mahon himself correctly pointed out, there is no mention of a similar painting in the Duomo of Ferrara in Guercino’s book of accounts, neither in that year, nor in the previous year. What is even more surprising is that there are no payments by Cardinal Magalotti to Guercino in those years. It is thus obvious that Malvasia does not necessarily refer to the altar painting in the Duomo in Ferrara but rather to another work, which must certainly have been made.
He was actually referring to the work in this exhibition. Everything is explained by a re-examination of the history of Lorenzo Magalotti and the work that has now been rediscovered. Lorenzo Magalotti had close links with Rome from 1624, when he was made cardinal, until 1628 when he became Bishop of Ferrara. During those four years, he was very close to Urban VIII and carried out important diplomatic missions as protector of the church of Santa Maria della Concezione in Rome where a chapel was to be dedicated to his patron saint. Guercino had to start work immediately but, in fact, the painting never reached its destination because the Magalotti chapel in the church of Santa Maria della Concezione was never made.