This work poses two main problems. The first is its assignment to the Buen Retiro group, and the second, directly linked to the first, is its date. In 1961 Marcel G. Roethlisberger noted the painting’s possible link to the palace, but did not consider it one of those works originally commissioned because he was unable to find mention of it in the testament of Charles II.

Barbara Von Barghahn did find it listed there, but her opinion was not taken into consideration by later scholars.

In fact, there is considerable proof that it is part of the Buen Retiro group. On its lower left the work bears the number 180 in white, corresponding to its inventory number in Charles II’s testament, in which it appears as part of the gallery of landscapes. On the far right the name of the Spanish monarch Philip IV appears on a tombstone. A very worn and barely identifiable coat of arms above the inscription may possibly be that of Manuel de Moura, 2nd Marquis of Castel Rodrigo, who managed the Roman part of this decorative project. Identifications like this are a frequent device in Rosa’s works, and can be seen in View of a bay, 1640 (Galería Estense, Modena), or Seascape with lighthouse, 1641, a work commissioned in Florence by Prince Giovan Carlo de Medici (Galleria Palatina di Palazzo Pitti, Florence), which shows the galleys of Santo Stefano bearing the Medici coats of arms on their sterns. Moreover, the manner in which this work is rendered with extremely light glazes over a dark primer, both in the vegetation and the sky, suggests that Rosa carefully studied the works of Herman van Swanevelt and Andries Both, who also painted for the Buen Retiro project.

The chronology of A harbour scene has also been subject to debate. Hermann Voss considered it contemporary with Rosa’s Florentine paintings (now at the Palazzo Pitti, Florence, and the Cleveland Museum of Art), which he judged to be between 1640 and 1645. He assigned the same date to the present work, and this was accepted by Alfonso E. Pérez Sánchez and all later scholars who studied it. However, this painting shows Rosa’s style in an earlier state, with a more summary line in both the vegetation and the architecture, as well as in the anatomy of his figures. In fact, some of the latter, such as the semi-nude character with crossed arms, appear in earlier works. All of this indicates that the present work was painted just before the three he made for Francesco d’Este, Duke of Modena, in 1640.

While there are numerous seascapes among the Buen Retiro works, there is no record of any having been commissioned in Rome. That makes this work a rarity. Its presence is a new indication (as also occurs with Claude Lorrain) of the freedom with which painters involved in this project occasionally interpreted their commissions (Úbeda de los Cobos, A.: Italian Masterpieces. From Spain´s Royal Court, Museo del Prado, 2014, p. 212).