With the invention of writing, the oral became the written tradition. This occurred in Greece and Rome, where genealogies were recorded in poems and in histories. But genealogy did not at this stage become a science, because when writers dealt with it, they did so either incidentally in their narrative or because they were concerned with the family relationships of their gods.

The historian Edward Gibbon’s observation that “the proudest families are content to lose in the darkness of the middle ages, the tree of their pedigree” may be challenged in the light of recorded genealogies. The male line of Charlemagne has been traced to St. Arnulf, bishop of Metz, who died about 635. Several royal line descents are traceable to the 6th century, as, in England, is the tree of Louis Mountbatten, 1st Earl Mountbatten. The ancestry of Queen Elizabeth II goes to Egbert of Wessex (about 825), beyond him to Cerdic (c. 500), and, if another series of names is accepted, to Woden (an actual man later divinized by the Germans), in the 3rd century ce.

With the conversion of the peoples of Ireland, Wales, and England to Christianity, the recording of their regal traditions began. It was natural for the first chroniclers, who were mostly monks, to write down the oral pedigrees of the kings in whose realms they lived. Students of the Irish regal pedigrees are prepared to accept two or three generations before the time of St. Patrick (flourished 5th century ce) as genuine, and it is quite probable that name lists of the Irish kings are valid back to the 3rd century ce. Similarly, in Wales, the ancestry of the greatest Welsh families can be traced for a millennium. Among the Anglo-Saxons there were similar bardic pedigrees recorded by monastic scribes, and many of these might have survived but for the destruction of the Old English ruling class during the Norman Conquest. A regular feature of such old pedigrees recorded by monks was an attempt to link them with the genealogies of the Scriptures. In an Anglo-Saxon pedigree of great length—that of the kings of Wessex (the ancestors of Elizabeth II)—the line is thus traced to Sceaf, “a son of Noah born in the Ark.” In the process of working out the connection between scriptural and regal genealogies, the monks adopted a reverse technique to that of the 4th-century-bce Greek mythographer Euhemerus; i.e., they downgraded the old gods to human status.

From roughly 1100 to 1500, the emphasis of genealogists was on pedigrees of royal and noble lines. Claims to a throne, as with the dozen or so claimants to the Scottish crown after the death of Alexander III in 1286 and of his direct heir, Margaret the Maid of Norway in 1290, frequently involved genealogical trees. The truth was sometimes bent to suit some political end, but, on the whole, medieval European records are genealogically valid. This is because they were not primarily intended to supply genealogical information but to record land transactions, taxation, and lawsuits. The facts of family history are incidental and are therefore generally reliable. Exact dates of birth, marriage, and death are rarely given. A man is said to be of age “by Michaelmas 1330.”

This period also saw the emergence of pedigrees of lesser folk. Land transactions involved claims in the local courts of the lords. Serfdom gave way to villenage; the latter involved so many days of labour on the lord’s demesne and also the inability to move from the estate without the lord’s consent. There was strong inducement for a man to prove that he was not a villein and for the bailiff to show that he was. In several parts of England, pedigrees of villeins or persons claimed as such have been worked out over periods of 100–150 years.

It was during the third period in European genealogical history that records that came to include everyone began. This period extends from 1500 to the present. As feudalism gradually gave way, new classes of citizens arose. In England the appearance of a powerful mercantile and business community was reflected in the growth of the middle classes, from which was continually recruited a new nobility and gentry. In turn, owing to the English rule of inheritance by primogeniture and the fact that unlike the continental nobility English nobility has never extended beyond the reigning peer and his wife, the middle classes themselves continually received the younger children of peers and gentry. Two other factors leading to the proliferation of records were the enormous changes caused by the Reformation and the great reemphasis on individual religion and the desire of Renaissance monarchs to have more exact information about all their subjects.