Intense cold can inhibit the physical and chemical reactions that over time destroy natural organic materials. The principles of freeze-drying under normal atmospheric pressure are enunciated. For treatment, the Marseilles shipwreck was enclosed in a large, airtight container filled with a dry inert gas, in this case nitrogen. The structure of the tank and equipment used to circulate the gas around the shipwreck are detailed; the object's size, composition, general condition, and weight imposed special constraints which are discussed, as are the precautions taken with the use of nitrogen. It is concluded that the process is highly practicable for large objects or large quantities of smaller objects of like composition such as archaeological fragments.