Once parties have agreed to buy and sell, the question arises as to when the risk of damage, deterioration or destruction of the thing sold and bought passes from the seller to the buyer.  As a starting point, the owner of the thing carries the risk of destruction or damage.  In many instances, the thing will pass from the seller to the buyer immediately upon agreement being reached with no problem as to the risk and when it passes.  However, there are circumstances in which a passage of time may seperate the point of reaching agreement (at which stage the obligations come into existence) from the moment of transfer of the thing.  If something should happen to the thing in the mean time, who carries the risk?

Romans distinguished several stages in the course of the act of agreeing to sale and purchase.  One of the most important moments in this progression of stages was what was referred to as the moment in which the agreement became perfecta, i.e. when the agreement became perfected, that is when the obligations created by the consensus became enforceable against the parties.  This occurred when all suspensive conditions had been fullfilled, the agreement was no longer dependent upon any terms of time, and all that remained was transfer of the thing sold to the buyer, and payment of the price agreed.

Suspensive conditions are those agreements in a bargain that have the effect of suspending finalisation of the agreement pending the fullfillment of the conditions, in other word, the parties agree that until something happens or has been done, the obligations created by the agreement remain unenforceable.  For example:  Atticus buys a villa in Naples from Bucolicus for a 1 000 000 aureii.  They agree, however, that Atticus will only pay Bucolicus once the latter has arranged for the repair of certain statues in the gardens.  Unless Bucolicus makes the arrangements (and one assumes (in the absence of it being particularised) also has them executed) for the statues to be repaired, Atticus has no obligation to pay the purchase price.  Once Bucolicus fullfills his end of the bargain (arrange to have the statues repaired), Atticus is obliged to pay.

What happens if between the agreement and the repair of the statues, an earthquake causes extensive damage to the villa itself?  Who bears the risk involved?

The Romans assumed that in principle, the seller had an obligation to reasonably ensure the proper maintenance and safety of the thing involved, and where the damage was caused intentionally by the seller, or because he did not exercise reasonable care in caring for it, the purchaser could claim such damages from him in all instances where the damage arises before perfection of the agreement.  In the case of damage caused by an act of the gods, for which obviously the seller could not take responsibility, such as an earthquake, the risk fell to the purchaser in terms of the maxim periculo est emptoris (= the risk is for (the account of) the buyer).  This arrangement was one by virtue of law, and came into operation from the moment the agreement was entered into.  Parties were, however, at liberty to vary the risk arrangement by a specific agreement to that effect. 

While this arrangement could be onerous for the buyer, the advantage was that he also had the benefit of fruits (e.g. where a female slave gave birth) or an increase in the value of the thing in the time between agreement and the transfer.  If the repair of the statues increased the value of the villa by a large amount, it was bad luck for the seller – he was held to the price he had agreed even though the agreement has not yet been perfected.

At the moment the agreement was perfected, the risk arrangement changed.  The buyer was now obliged to take delivery and transfer of the thing.  Where he did not, he carried the risk for all damage except any intentional acts of the buyer giving rise to damage.

*   Many thanks to Clockmaker who noticed the transposition of names in the example. I hope it is now fixed.