Originally created as The Rôles d'Oléron and first adapted in Castile by Alphonso X in 13th century France, the Code read as follows:
"Know all men that We, with the aid of upright counsels have laid down these ordinances.....
"Whoever shall commit murder aboard ship shall be tied to the corpse and thrown into the sea.
"If the murder be committed on land, the murderer shall be tied to the corpse and buried alive.
"If any man be convicted of drawing a knife for the purpose of stabbing another, or shall have stabbed another so that blood shall flow, he shall lose a hand.
"If a man strike another with his hand, he shall be ducked three times in the sea.
"If any man defame, vilify, or swear at his fellow, he shall pay him as many ounces of silver as times he has reviled him.1
Thus the later Middle Ages saw their first true code of conduct for navies. The Roll of Oleron was formulated and drawn up by the Republic of Rhodes and was accepted and practiced by the Roman Empire and most neighboring Mediterranean states and nations.
The Code was first introduced to England by King Richard I (who was crowned in 1189 A.D.) and was referred to extensively in the travel to the Holy Lands in the second year of Richard I's reign. The Code of Oleron was one of the very first code of rules accepted nearly universally throughout western society and was very plainly not a kind set of laws. The Code demanded calculated and painful punishment to keep all seafarers under control.
It is also of note that The Code of Oleron was heavily cross referenced as well as a building block for the Black Book of the Admiralty, a slightly more modern set of British naval rules.
Sources
1http://www.gunplot.net/navalhistory/originofnavy2.html
http://www.britannia.com/history/monarchs/mon27.html
http://www.infoplease.com