Magister Navis

• In Roman Law, the Owner, the Exercitor Navis, had the legal responsibility for the cargo and passengers he contracted to transport.

The Exercitor Navis (The Owner)

• The Exercitor Navis could choose anyone to be subject to his Authority or in Latin, Alieni Juris, even a Slave.
• He would then appoint him as Magister Navis, meaning captain of his vessel.
• The Owner then granted the Captain ‘Praeposito’, meaning ‘placed in command’.
• The Captain became the legally Appointed Person to manage the Owner’s affairs and undertake contracts to be hired on his behalf.
• The shipper at the other end could then negotiate with the Magister Navis, without ever having to meet the Exercitor Navis in person, who could be thousands of miles away.

Ownership and Possession

• Under the Lex Rhodia, the Captain was the ‘Possessor’ and the Shipper was the ‘Owner’.
• If  the Captain lost the cargo or pirates robbed it whilst it was in his ‘Possession’, (ie, on board the ship he commanded), then the Captain was liable, not the Owner.