Origionaly Lathom, named after the Lancastrian town and parish near Ormskirk in the outskirts of Liverpool, UK. The town took it's name from the (old) Norse (Scandinavian) word "hlatha", barn.
Lathom in Lancashire is recorded as "Latune" in the Domesday Book of 1086, and in the 1201 Pipe Rolls of the county as "Lathum". "Laytham" in East Yorkshire appears as "Ladone" in the Domesday Book.
After the Norman invasion, a Saxon warlord by the name of Dunning was named "de Lathom" by the Norman Court. The town already existed. Dunning, being Saxon would have previously been know as Dunning Fitz (his fathers Christian name).
Some call him a traitor to his people, for he collaborated with the Normans during their invasion in 1066. Perhaps he didn't have much of a choice in the matter; it could be his family or the entire town would be put to the sword if he didn't assist the Normans. We'll never know, for it was not recorded to my knowledge. For assisting the Normans they gave Dunning the Lordship of the Chapelry of Lathom, Lathom house and its' surrounds, (the town of Lathom itself would later become a part of Ormskirk, Lancashire, England).
Sir Dunning de Lathom, 1st Earl of Lathom. In the Spring of 1067 A.D. Born: Abt.1031, married Lady Marigard de Essex of Essex & Avon on 28 May 1068, Chapelry of Lathom, Lathom, Lancashire, England.
He is the earliest known person to bare the "Lathom" surname.
From Miscellanea Palatina, 1850: Dunning, father of Siward, the earliest proprietor named in this Inquisition, would be coeval with Domesday. It is not quite certain whether the Lalune of that Survey, situated between Ribble and Mersey in Derby Hundred,' relates to Lathom (Ladhun), nor whether Dunning was a continued possessor or a Norman grantee, but his name, which was the name also of the Lord of Kingsleyin Cheshire, a Saxon suffered to continue, marks his race.
He Died: 12 Oct 1092, Lathom House, Lancashire, England. Interred: Chapelry of Lathom Cemetery, Lathom, Lancashire England.
Normally, locational surnames were acquired by those former inhabitants of a place who moved to another area, and were thereafter best identified by the name of their birthplace. The modern surname can also be found as Laytham, Leatham and Lathem. The marriage of John Leatham and Kathleen Lee was recorded in Carlton near Snaith in Yorkshire on January 28th 1626. The first recorded spelling of the family name is shown to be that of Robert de Latham (witness), which was dated 1204, in the "Yorkshire Assize Court Rolls", during the reign of King John, known as "Lackland", 1199 - 1216. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.
One variation of "Latham" (as opposed to Lathom) occured around 1690. The Lathom's of Allerton had had their lands and heriditaments confiscated by Parliament for their part as Royalists in the English Civil War. Many of the families, reduced to poverty and wanting in education, allowed the varied spelling in the various birth records. One out of four brothers were named Lathom whilst the others were named Latham.