Uradel (German: "ancient nobility"), refers to the oldest nobility, and not nobility acquired through letters patent or the likes. It is applied to designate those knightly families in northern European nobility whose noble rank predates about 1400 A.D. The term came into use in the 19th-century.
Germany and Austria
To the Uradel count noble houses respectively families, whose ancestral lineage can be demonstrated to predate no later than around 1400 A.D. (Middle Ages) who belonged to the knighted (German ritterbürtigen) nobility. Knightship (Ritterbürtigkeit) set in the Middle Ages, by rule, a requirement for at least three-generations of knightly life, as well as befitting marriages in ones social class, so that even the late (after 1350 A.D.) documented mentioned knightly families, are likely, by rule, to have had at least a century of belonging to this status.
In contrast, Briefadel (letters patent nobility), count families of post-medieval nobility, who were originally from civil (Bürger) or peasant origin, ennobled by letters patent issued by a monarch, usually with the award of a coat of arms (if not already present). Allegedly influenced by French practice, the earliest letters patent conferring nobility in Germany were issued under Charles IV (r. 1346–1378).
The Uradel term was first used in 1788 to designate the oldest nobility, and assumed its present-day meaning no later than 1800. The term is found in the Almanach de Gotha from 1907, where it applies to all persons and families known to have carried specific titles of nobility before the year 1400.
Uradel and other noble families are generally further divided into the categories adlig (noble), freiherrlich (baronial), gräflich (comital), and fürstlich (princely and ducal) houses. According to a more strict definition, described in Der Große Brockhaus in 1928 (vol. 1, s.v. "Adel"), an attestation prior to 1350 is required to establish Uradel status.
A similar term used more often than Uradel in Austria was alter Adel ("old nobility").
The 1926 edition of the Swedish Nordisk familjebok also cites 1350 as the required date, because "the oldest known letter patent dates to 1360". The letter patent referred to here is that issued by Holy Roman Emperor Charles IV to Wicker Frosch, a burgher of Frankfurt, on 30 September 1360. In Norway, one of the earliest known letters patent is of 1458.
- Godsey 2004, p. 58.
- Duden; Meaning of Uradel, in German. 
- Ursula Siems, Kurt Kluxen (1979). "Politik, Gesellschaft, Wirtschaft von 800 bis 1776". In Tenbrock, Kluxen, Grütter. Von Zeiten und Menschen 2. Paderborn. pp. 39–41.
- William D. Godsey (18 November 2004). Nobles and Nation in Central Europe: Free Imperial Knights in the Age of Revolution, 1750-1850. Cambridge University Press. pp. 57–59. doi:10.1017/CBO9780511496752.004. ISBN 978-1-139-45609-8.
- Jacob Grimm, Deutsches Wörterbuch erst im 19. jh. gebraucht zur bezeichnung ältesten adels. ("in use only from the 19th c. for the designation of older nobility"), citing Eichhorn (1821, 1827).
- Granichstätten-Czerva, Rudolf von (1947). "Altösterreichisches Adels- und Wappenrecht". Adler. Zeitschrift für Genealogie und Heraldik (1.4): 49–58.
- Salmonsens Konversationsleksikon (1915: 169)
- Nordisk familjebok (1926:1120)
- Godsey, William D. (2004). Nobles and Nation in Central Europe: Free Imperial Knights in the Age of Revolution, 1750–1850. Cambridge University Press. ISBN 9781139456098.