Reynolds in the Discourses usually refers jointly to the Florentine and Roman schools, and this is unsurprising in view of the close, if not always harmonious, political, social, and intellectual relationship between Florence and the Papal court. At Works, 21.20 Ruskin contrasts the 'Tuscan schools of thought' with the 'Roman schools of technical design'. However, the Florentine Michelangelo, and Raphael, who despite being born in Urbino developed his mature style in Florence, were at the heart of the development of painting in Rome as in Florence.
A clear distinction is made by Ruskin at Works, 22.101 between the influence of Michelangelo in Rome and the work of the Venetian Tintoretto. Ruskin comments on the Last Judgment of Michelangelo in the Sistine Chapel that 'some farther evil influence is due to the fact that Michael Angelo has invested all his figures with picturesque and palpable elements of effect'. Tintoretto, in contrast, in the large Paradise has only made his figures 'lovely in themselves, and has been content that they should deserve, not demand, your attention'.
Giulio Romano (died 1546) was an assistant of Raphael; he was influenced in his work by both Raphael and Michelangelo; his work was admired by the Florentine Vasari; and 'Romano' is not a family name but a descriptive adjective. Giulio Romano was called 'vicious' by Ruskin at Works, 6.447, and 'false and bad' at Works, 15.345.
At Works, 20.124 Ruskin cites the Florentine Leonardo da Vinci and Raphael as examples of the Roman school. In Modern Painters IV ( Works, 6.65) Leonardo da Vinci, in contrast with Turner, is one of those painters who 'endeavour to get rid of the idea of colour' and 'invariably exaggerate shadow'. The 'ruffian Caravaggio' (1571 - 1610) who gained his reputation and his following in Rome is cited in Ruskin's review of Lindsay's' The History of Christian Art' as an example of someone who fails to see in nature what is truly there, and he uses 'black shadows for the reinforcement of villainy' ( Works, 12.202). In a letter to his father from Parma on 10 July 1845 ( Works, 4.xxxv) Caravaggio appears as a member of the 'school of errors and vices'; at Works, 4.213 Caravaggio feeds 'upon horror and ugliness, and filthiness of sin', and at Works, 5.56 Caravaggio, Salvator Rosa and Teniers are 'worshippers of the depraved'.
Federigo Zuccaro established the Rome Academy - the Accademia di San Luca - in 1593; Ruskin refers to his 'vile frescoes' in Florence at Works, 4.306
Perhaps for Ruskin the use of the term 'Roman' school carries with it connotations of the art of the Counter-Reformation and of Roman Catholicism which for Ruskin at 'had never shown itself capable of a single great conception since the separation of Protestantism from its side' ( Works, 9.58).
Kugler, ed. Eastlake, Handbook of the History of Painting, Part One, The Italian Schools, First Edition, page 384 comments that 'the completest degeneracy is to be found in Rome'.