The coat of arms began to be used as a hereditary device in England in the mid-twelfth century. Each coat of arms belongs to a particular family and no two families are allowed to bear the same arms. This means that a coat of arms, for example on a funeral monument or a seal, should in principle identify the associated family unambiguously. The arms passed to younger sons as well as the eldest, though they were often altered (or differenced) in some way to indicate this - eventually an elaborate system of marks of cadency was developed to indicate the arms of younger sons (and also those of the eldest son during his father's lifetime). The main contemporary source for medieval heraldry is the rolls of arms. These were practical documents, which often recorded the knights present at a particular battle or tournament.

Coats of arms can also convey information about marriages and maternal ancestry. If representatives of two armigerous (i.e.arms-bearing) families married, the union would be represented heraldically by a composite shield of arms, the husband's on the viewer's left, and the wife's on the viewer's right.

Quartered arms on monuments and in pedigrees often represent marriages that took place a century or more earlier. When it came to identifying quarterings, whether by heralds at the visitation or later antiquaries, they could easily be attributed to a different family with similar arms. Conversely, the arms provided could be those of a different family of the same name, or the quarterings could belong to a different branch of the same family. To identify a coat of arms, the tinctures have to be known, as well as the rest of the design. The same is largely true of arms on monumental brasses (although sometimes traces of colouring may remain on brasses, and conventions did exist for indicating tinctures when engraving brass. And painted arms, in modern times, can be given a nice new coat of paint, which sometimes bears little relation to the original colouring.

The visitations produced a collection of pedigrees of families with the right to bear arms, recorded between the early 16th and the late 17th century, but in many cases extending much further back. The College of Arms was not formally incorporated until 1484, and the system of visitations did not get under way until the following century. By that time, of course, many families who had borne arms previously were extinct, or they may be assigned a surname with no indication of time or place, such as one Tudor herald. Despite the elaborate rules governing the marshalling of arms and the addition of marks of cadency, it is impossible to work back from a coat of arms and deduce the shape of the pedigree, as quartered arms should occur in a precisely determined order. But there is nothing more than a mark of cadency to indicate in which generation the marriages took place and, because each marriage can bring in more than one quarter, there are always.

From the early 16th century to the late 17th century the heralds carried out visitations, county by county, in order to regulate the use of arms. Most counties were visited several times during this period. The Visitation of London begun in 1687. Those who were allowed arms had them recorded, including the quarterings to which they were entitled. Sometimes the heralds also recorded some of the evidence on which the pedigree was based, such as transcripts of medieval charters, drawings of seals, coats of arms copied from churches or private houses and so on. Most importantly to the genealogist, supporting pedigrees were recorded. These could include, in addition to the main line of descent, offshoots giving the ancestry of wives who were heraldic heirs, in order to illustrate the route by which the quartered arms had been acquired. In these pedigrees, dates are given only occasionally, and presumably reflect the dates of documents which mention the people concerned. Often the ages of those in the final generation are given, which can allow the chronology of the later part of the pedigree to be estimated.

The College of Arms in London remains the official body responsible for granting coats of arms and regulating their use in the United Kingdom (except Scotland). Their collections contain most of the original books of visitations and a huge volume of miscellaneous genealogical and antiquarian notes, probably including much otherwise unrecorded evidence. Another significant class of records are the funeral certificates, dating from the late 16th to the early 18th century. These accounts of heraldic funerals contain, in addition to heraldry, details of death, burial, marriages, children and so on. Coats of arms have been and still are granted by Letters Patent from the senior heralds, the Kings of Arms.