In 1778, shortly after Ducros's arrival in Rome, he was employed by the Dutchman Nicolas Ten Hove to accompany him to the Kingdom of the Two Sicilies. This 'Grand Tour' took him to southern Italy, Malta and Sicily, where he painted topographical views of Mediterranean landscapes and ancient monuments, and was to have a decisive effect on his career. The drawings he took back with him provided a repertoire of ruins, views and picturesque scenes which he re-used in his later work.
On his return to Rome Ducros went into business with the engraver Giovanni Volpato (1732-1803), well known for his hand-coloured prints of Raphael's loggie and stanze at the Vatican. They published several series of handcoloured prints of views of Rome which were immensely popular. Ducros' first large pictures were oils commissioned before 1784 and it is unlikely that he painted watercolours of a similar size before that date. His decision to use watercolour on such a grand scale was probably due to the success of the large hand-coloured prints and the activity of artists such as Jacob Philipp Hackert (1752-1797) and John Robert Cozens (1737-1807) who were also working in Rome at that time.
Some of Ducros' watercolours are on a single sheet but most, like this one, are the result of several sheets joined together to obtain the desired larger format. This allowed him to paint landscapes of an exceptional size which were then laid down on canvas and mounted onto a stretcher in order to preserve and exhibit them. Most were framed and put under glass and the artist clearly intended them to compete with compositions in oil.
In 1782 Ducros moved to a gallery and studio in the Strada della Croce where he remained until 1793, the year he was forced out of Rome by a group of jealous artists who had implicated him in the murder of the French diplomat Hugou de Bassville. By his own account he had been falsely described as 'a very dangerous man, attached to the French Republican party' and so fled with very few belongings to Naples. In a letter dated 1 April 1799 to the Paris Directory, from whom he was trying to gain compensation for his losses in Rome, he included a studio catalogue of Des Vues de Rome et des environs peintes, a l'acquarelle chez LOUIS DU CROS peintre de Paysage rue de la croix à Rome.'. In the accompanying letter he writes that he had 'a collection of coloured views... which were a profitable employment for [his] firm' and it is possible that this present watercolour is no. 21 'Vue de l'exterieur du Pantheon' from this catalogue.
Although trained as a topographical view painter, Ducros was influenced by Panini, Piranesi and Hubert Robert, evident in his treatment of ancient monuments and architecture. His use of watercolour rather than oil gave him greater freedom of expression, allowing him to play with light and shade and to modulate colour, all of which he demonstrates in this impressive sheet.
Another watercolour of the Pantheon but of smaller dimensions and over etched outlines was sold in these Rooms, 15 June 1976, lot 238.