Christopher Columbus

Christopher Columbus was a Genoese navigator and explorer who, amongst other things, discovered America in 1492.

While renowned for his discoveries, he was also a cruel man, who used American natives as slaves and, as a colonial governor, committed many atrocities. (AUDIO: Trouble in Paradise)

Encounters with the Doctor
During or before his fourth incarnation, the Doctor travelled with Columbus on the Santa Maria, and suggested that Columbus plot his course with an orange and a biro, but Columbus didn't listen. (PROSE: Eye of Heaven) At some point The Doctor acquired his business card. (TV: The Two Doctors)

The Sixth Doctor and Peri Brown later met Columbus in 1492 when they were summoned to his ship by the Doctor's eleventh incarnation. (AUDIO: Trouble in Paradise)