<human>:  Why did the Argonauts sail to the island of Colchis?
<bot>: The Argonauts sailed to Colchis to obtain the golden fleece. The fleece was said to be able to make anyone who wore it invisible. The Argonauts had to retrieve the fleece from the palace of King Aeetes. King Aeetes was not a nice person and he had a pet dragon named Ladon that guarded the fleece.