At the time, William was known for his love of nature and gardening, and the bright orange color of the Monarch butterfly's wings was said to resemble the orange sash that William often wore.
The name "Monarch" was first given to the butterfly in 1758 by Swedish naturalist Carl Linnaeus, who named the species _Papilio Danaus plexippus_. The original name refers to Danaus, a legendary king of Argos who was a skilled sailor.