Explanation: Contrary to modern archeological ethics and thinking, wherein cultural artifacts should remain, as much as possible, in the milieu they originated in, and peoples have a right to the artifacts originating from their nations, during the birth of modern archeology, in the 19th century, the thinking was much more... imperialist. Numerous items, both recent and ancient, were plundered by European powers to be displayed in museums.

Now, on one hand, it must be recognized that this is actually a step up from what used to happen when one power looted another - the slapdash accumulation of priceless artifacts in the hands of largely private individuals, many of whom only valued the items for the worth of their precious metals or gems. Innumerable artifacts throughout the ages have been damaged or melted down for this very reason - by all cultures.

On the other hand, "We're stealing this to preserve it, not to melt it down!" is... a step up from stealing it to destroy it, but only just. It still doesn't justify the theft.

Britain, in particular, has a very nice museum with lots of artifacts, many of which have unsavory 19th century provenances, and some of which are still involved in international disputes to this day!