The Heralds' Visitation is the process of checking 'achievement' (or entitlement to bear a coat-of-arms). The heralds were sent out by the Royal Court to ascertain whether a person was entitled to a coat of arms or not. They would visit an area and set up what amounted to a court and all the armigers of the area had to present proof of entitlement by showing lineage to the original armiger who obtained the arms. Those who could, kept their entitlement; those who could not had their arms (achievement) struck down. The Visitation contains full pedigrees (tree diagrams) of some families, in alphabetical order, as at the Visitation date. (An index is included, as each family also contains names of other people marrying into the family). The Visitation may also include transcripts of parish registers and other notes relating to some families. The pedigrees in many cases go back many generations before 1620 to Norman times.

• The Herald's Visitation of Cornwall 1530, 1573 and 1620 are available on-line. These were originally published by the Harleian Society in 1887 and which which is an amalgam of the original editions of 1530, 1573 and 1620 with additions by the editor from other sources e.g. parish registers.
• There is also one published by Archive CD Books which is the 1874 volume (and which is a straight reproduction of the visitation of 1620 with a commentary). This latter is of much higher quality (more room, bandwidth, better scanner etc.); however, the former book is the more useful to researchers.