The accurate statements about the voyages of Christopher Columbus are:
A) He concluded that the lands he reached were part of Asia.
D) His voyages proved that the world was round.
While his voyages did contribute to increased European exploration and led to discussions about land claims, the signing of a treaty specifically due to his voyages is not directly accurate as presented in option B. Additionally, he did not set out to circumnavigate the world, which makes C incorrect.