Publius Crassus
Strabo says that a Publius Crassus was the first Roman to visit the Tin Islands and write a first-hand report. This Crassus is thought to be either the Publius Licinius Crassus who was a governor in Hispania in the 90s, or his grandson by the same name, who in 57–56 BC commanded Julius Caesar's forces in Armorica (Brittany), which places him near the mouth of the Loire river.