Recorded as Treat, Trett, Trette, and Tretter, this is apparently an English surname. It is well recorded in the surviving church registers of thge diocese of Greater London from at least early Elizabethan times, with perhaps the first recording being that of Joane Trett who married John Robe at St Gregory's by St Pauls Cathedral, on August 10th 1567, and a decade later that of Alyce Treat, who was christened at St Giles Cripplegate, on May 13th 1576. However neither of these recordings or indeed any of the others in the registers, given any indication as to the origin of the surname. In our opinion based upon research of over one hundred thousand surnames, we believe that there are two possible sources. The first is from the French word 'tretier' meaning to treat, and hence maybe a description for a doctor or vet, or it may be a shortform of a personal name. The Olde English pre 7th century Theobald, or perhaps the later Norman-French Theodore are possibilities as between them these names which were very popular in medieval times, are known to have been the source of over fifty variants. These are known to include Tebb, Tett and Tibb, showing that anything is possible with names.