Urgent relief imposes two basic requirements which influence both the procedure and the structure of the trial in which it is applied: avoiding prejudice and, in order to avoid prejudice, deviating from the general rules of procedure.

As Calamandrei rightly noted in his fundamental work of 1936 (recently reprinted), the duration of the ordinary suit can lead to the danger that measures taken will be both useless and tardy. This is not a new viewpoint: it was a valid dictum in the Roman trial that “Si periculum est in mora, receditur a regulis iuris communis”.

The thing which is new in our times is the consciousness in democratic legal systems that the judicial protection of rights and legitimate interests is not effective unless it is quickly obtainable. This observation applies to ordinary commercial rights, but above all it applies to non-commercial ones, for example rights of the person and his liberty. In other words, the time factor has become a vital one in guaranteeing and effecting access to justice.

It is well known that the United States Constitution establishes the right to a speedy trial. Article 6 of the European Convention on Human Rights similarly states that everyone has the right to have his case decided “dans un d61ai raisonable”.

The sale of property by a non-owner is an important question in many legal systems. The problem is more acute in the case of movables, since with immovable property the existence of a register of title allows the buyer to check with relative ease whether the seller is in fact the owner. There is usually no register of title to movable property, and the buyer will usually identify the holder of goods who is offering them for sale as their owner.

There are three parties involved in the problem: A — the real or original owner, B — the seller, and C — the buyer. B may be a thief, a finder or A's bailee, or he may have obtained the property from A by misrepresentation, and so forth. In many cases it is impossible to obtain satisfaction from B, either because he cannot be traced or because he is insolvent, and the question of who owns the property, A or C, then assumes vital importance.