Outstanding topic!!! and great observations.
I have always been fascinated by Rembrandt's paintings, particularly the presence of weapons used that were completely out of context historically, as described here. Also, one of my favorites, the so called 'Polish Rider' and the presumably correct weapons which were likely used by the horsemen of the 'cossack' units presumed being portrayed in this work.
Rembrandt began painting in what was known as historical painting, so the theme of his works were often Biblical or mythological subjects, but as with most artists, he imbued his work with his own perspective and used metaphor, symbolism and allegory. In "The Biblical Rembrandt" (John.I.Durham, p.76), the author notes that Rembrandt considered the Bible, or his interpretations of it extremely personal and identified with its stories in many ways, and in this sense, I would suggest may have imbued much of himself into these Biblical stories he painted.
It would seem that his deep interest in collectible items and curios was likely heightened by the fact that he was established as a portrait artist, and patronized by presumably well to do clients, many of whom were probably merchants. These merchants undoubtedly had access to a variety of exotic items from the East Indies, including weaponry, and it would not be surprising that some of these might have been gifts to Rembrandt, or been included in payment possibly. With the consideration that he considered these exotic weapons an element in degree of his own personality, perhaps this might have been a reason for using them in such incongruent context. Certainly the idea that their formidable appearance, such as the wavy bladed keris, might have been meant to elicit fearsome intent as well.
There is an even more remote thought concerning the wavy blade of the keris as applied to Biblical metaphor in Rembrant's painting. Recently there have been discussions of the 'flammard', or wavy bladed sword, as seen on some early rapier blades, as well as a number of edged weapons, and thier allusion to the Biblical account of the sword guarding the gates of Paradise.
While this may be considered with respect to the keris in Rembrandt's art, the same perspective would not apply to the polearm which appears to be Sinhalese, nor the swordlike weapon falling out of the hand, which seems to be a polearm head used as a sword without the shaft.
Although classical art, such as Rembrandt's discussed here, can lead to obvious issues in weapons study in many cases, it is interesting that in portraiture, where metaphor and allegory are not typically involved, the weapons shown are often quite accurate. The key example of this that comes to mind is "The Smallsword and Rapier 1460-1821" by the late A.V.B. Norman, which is a brilliant work using period artwork and portraits to establish hilt and pommel typology on these weapons.
Returning to Rembrandt, the art historian Gary Schwartz remarked that a weapons and tool expert with whom he had studied the weapons shown in 'the Night Watch' was a bit 'contemptuous' of Rembrandt's offhand way with weapons, as some of these were apparantly of earlier periods.
It would seem that this would suggest that weapons that appeared impressive were perfectly acceptable as long as they carried the theme.
In this case the men were essentially a semi military social club at the time, engaged in firing of guns and other associated activities for show, and likely may have had heirloom weapons at thier disposal. It is noted that some items in that painting may have been 16th century.
All best regards,
Jim
PS crossed posts, and just noticed Henk's and Lews previous note on the East Indies commerce and ships coming in returning from there. I also saw one reference that noted some of Rembrandt's critics grumbled about his associating and hanging around with 'low people'....I would imagine this would include trips to the docks....and sailors there with curio's and weapons.
