What event does the name 'Sandwich Islands' refer to?

The term 'Sandwich Islands' refers to the name given to Hawaii by Captain James Cook, who encountered the islands in 1778. He named them after the Earl of Sandwich, a patron of his voyages, to honor him. This name reflects the European exploration and discovery of the islands during that period. Captain Cook's arrival marked a significant moment in Hawaiian history, as it brought outside attention to the islands and set the stage for subsequent interactions between Hawaiians and Europeans, which would lead to profound changes in Hawaiian society and governance.

The other options relate to different aspects of Hawaiian history but do not connect directly to the naming of the islands. The treaty between Hawaii and the U.S. pertains to political agreements, the name change of Hawaii reflects broader history but not the origins of the name 'Sandwich Islands,' and the construction of Iolani Palace is related to the royal history of Hawaii rather than its naming.