This large, detailed panel is the oldest painting of the sea by a Flemish or Flemish-trained artist in the collection of the National Maritime Museum. It is one of the few contemporary paintings of ships of the first half of the sixteenth century and one of the best representations of the first generation of ocean-going merchantmen. The subject is generally thought to be the carrack 'Santa Catarina de Monte Sinai' bringing the Infanta Beatriz, second daughter of King Manuel of Portugal, to Villefranche for her marriage to Charles III, Duke of Savoy, in 1521. The Portuguese vessels are shown wearing Manuel's flags and emblems but were met by Italian ships during the journey from Lisbon. However, considering the distinctly Flemish style of the painting, this identification of the subject remains debatable - although Flemish artists did work in Portugal and Spain, notably (in the marine sphere slightly later) Hendrick Cornelisz Vroom. That said, in this case the original function of the painting and the identity of the artist remain elusive. An examination of the oak panel suggests that it was probably originally set in a wall frame or wall panelling and, therefore, could have been part of a larger decorative scheme. This may, in turn, support the hypothesis that it is the work of a prestigious painter, depicts an historical event such as the wedding voyage of 1521, and was possibly intended for a ‘public’ space.

The 'Santa Catarina' was richly adorned for the wedding voyage of the Infanta. Quarters were prepared for her, the Count de Villa, ambassadors and officials in the stern castle of the ship. These apartments were decorated with splendid fittings, fine silver and given a gilded finish. The Infanta's cabin was furnished with brocade, carpets and velvet cushions. The awning of the ship was of crimson velvet and white damask, with borders that were described as of velvet with tassels of silk, and lined inside with blue damask from China. There were two very large damask flags with the royal arms painted in gold and silver on the ship's stern. Another 84 large flags of crimson and white damask decorated the masts and yardarms. A band of musicians also accompanied the Infanta.

The painting depicts ten ships, a caravel, three galleys and a rowing barge, off a coastline on the right. This mountainous ‘world-landscape’ consists of a fortified tower on a rocky outcrop above a steeply rising walled town. A man-made harbour can be seen below. Inside the harbour are a number of ships. Two of these vessels are shown at anchor. Beyond this is another at anchor and one more coming to anchor. Wooded hills are visible in the background, on the right, and an island lies off-shore in the distance on the left. The scene is observed from a high vantage point. An aerial perspective is introduced through the warm brownish-green tones in the foreground which gradually change into cooler blues in the background.

In the centre foreground, the carefully delineated principal ship is a large armed Portuguese merchant carrack. She is shown firing a salute to port and starboard. This is thought to be the 'Santa Catarina', which was built of teak at Cochin, India, in 1510, to serve as one of the large armed merchant ships of the Portuguese East Indies trade. She is shown in starboard-quarter view. Figures on board are carefully delineated and are evident in both the rigging and main-top ('crow's nest'). Nine other ships of broadly carrack form are present, five under sail and the four at anchor. The two under sail, immediately flanking the 'Santa Catarina', are flying Portuguese colours and firing salutes from single guns towards her. The ships are a combination of four- and three-masters with a pair of two-masted galleys in the right foreground and middle distance. Beyond the far side of the harbour entrance a three-masted lateen-rigged caravel approaches in port-bow view. In the foreground the galley with crewmen visible, heading towards the 'Santa Catarina', flies Savoyard banners. From one of her starboard bow guns, the galley fires or returns the 'Santa Catarina's' salute. This and the dragon figurehead of the 'Santa Catarina' are visible through the artist's use of isometric perspective, which brings details into view that would not be seen from the perspective of the viewer.

The mainsail (technically a 'main course') of the 'Santa Catarina' is the biggest sail in the painting and consists of several elements. It has been extended by the addition of two (or 'double') bonnets, in the fine weather. Their fixing points have been coded by pairs of apparently random letters so that they match up correctly. One of these may be 'A T' in monogram form. However no artist is known with those initials. This painting has been variously and incorrectly ascribed to the Portuguese painter Gregorio Lopez (d. 1550), Pieter Bruegel, Cornelisz Anthoniszoon, c. 1500-55, and Hendrick Cornelisz Vroom. The land- and townscape show the influence of the Flemish painter Joachim Patinir, d.1524, and are Flemish in colouration and style. The National Maritime Museum aimed to clarify the attribution after Sir James Caird acquired the panel for over £2000 in 1935. In 1936, correspondence between the Museum and art historian Max Friedländer, as well as the Director of the Warburg Institute, Fritz Saxl, placed the painting between the oeuvres of Joachim Patinir and Pieter Bruegel. Friedländer dated the panel to 1540 and he supported the suggestion made by Charles Tolnay that the painting could be by either Jan or Matthijs Cock. A stylistic comparison with the rendering of the waves and the delineation of the rocks in 'The Martyrdom of St Catherine', in the National Gallery of Art, Washington, may tentatively support the latter attribution.

The only other contemporary painting to show Portuguese carracks, in similar detail, is the 'Santa Auta' altarpiece. This was formerly in the Santa Auta Chapel (c. 1522, to which the altarpiece is thought to be coeval) in the convent of Xabregas outside Lisbon: today it is in the Museu Nacional de Arte Antigua, Lisbon. Santa Auta was one of the mythical companions of St Ursula. The martyrdom of Santa Auta in Cologne is the subject of the foreground and the shipping is depicted in the background. In 1972 the Ministerio da Educacao Nacional, Institito de Alta Cultura, Centro de Estudios de Arte e Museologia, published a study of this (with reference to the painting held in the National Maritime Museum) entitled 'Santa Auta Altarpiece, A Research Study', but unfortunately it is not illustrated. Whatever its origin, the present painting exemplifies the emancipation of landscape and the sea. The artist has deemed both subjects worthy of large-scale, independent treatment and - at a very early date- has demonstrated their validity for paintings of considerable size. As far as currently known, it is the earliest surviving representation of a marine subject for a secular rather than religious purpose.