Sale (Roman)

A sale in Roman law is a contract for the exchange of a good, or goods for money.

Requirements
One of the two parties must be paying in cash for a contract of sale to be formed, and the amount of money involved must be greater than 0 (no sales for 0).

The price can either be a fixed set agreed price, or a price that is obtainable ( e.g. "Market Price" or "All the cash in (x)" (as long as not zero). Whether or not a third party could set this was disputed until Justinians's time, where it becomes a suspensive condition.

The Price must be "Adequate", in that it can't be used to give a gift by stealth with a ridiculously low price (although a low price in itself doesn't necessarily invalidate the sale on its own, the exception to this is If the seller receives less than half of the value of the land, he can rescind under the Laesio Enormis rule.

The seller had to provide vacant possession, and also had to guarantee against eviction.

Effects
An "Arra", or token, may pass between the two parties. Whilst not required to form the contract, it can stand as evidence of it. This can be part of the payment, or a ring, or some other token.

A sale is an agreement to transfer ownership, it does not transfer ownership; it is delivery that transfers ownership.

However the risk transfers to the buyer (or when separated from the others of their type that arent sold in the case of items that arent specifically identified). However this is tempered by the seller being required to take a high level of care (bonus paternus familiarus) to the item and to assign any rights in delict to the seller, and any fruits from the item.