The Oakeshott typology was created by historian and illustrator Ewart Oakeshott as a way to define and catalogue the medieval sword based on physical form. It categorizes the swords of the European Middle Ages (roughly 11th to 16th centuries) into 13 main types labelled X to XXII. Oakeshott introduced it in his treatise The Archaeology of Weapons: Arms and Armour from Prehistory to the Age of Chivalry in 1960.
The system is a continuation of Jan Petersen's typology of the Viking sword, introduced in De Norske Vikingsverd ("The Norwegian Viking Swords", 1919), modified in 1927 by R. E. M. Wheeler into a typology of nine types labelled I to VII by Wheeler, extended with VIII and IX by Oakeshott.
Among the many reasons for his Typology, Oakeshott found date classification unreliable at the time his research was conducted. He suggested that trade, warfare, and other various exchanges, in combination with the longevity of the weapons obscured the date of manufacture, use, and retirement.
Criteria of definition
Several factors are used to distinguish the types, most importantly blade characteristics such as cross section, length, fuller(s) and the taper of the blade toward the tip. The taper is the degree to which the blade narrows toward the point away from the hand. This may vary between a blade with straight linear edges that join at the end as an elongated triangle, or in others the edges may be entirely parallel and devoid of tapering, finishing in a rounded point. The fullers are grooves along the length of the blade, usually singular and in the center, though sometimes plural. The length and presence of these help distinguish categories. Type XXII typically have very short fullers, Type X have fullers that nearly reach the point, and Type XV generally have none at all. Grip length can vary within a type, as in Type XIII. For purposes of description, Oakeshott referred to the tip of the blade as the bottom, and end of the pommel as the top. This orientation is inspired by his observation that many blades bearing inscriptions and crests had to be oriented this way to be read correctly.
Oakeshott X describes the type of sword common in the late Viking age, remaining in use up to the 13th century. It features a broad and flat blade with an average length of 80 centimetres (2.6 ft) with a very wide and shallow fuller running almost the entire length of the blade but fading out just before the point (which is typically rounded). The grip has the same average length as earlier Viking swords of about 9 centimetres (3.5 in). The tang is usually very flat and broad, and tapers sharply towards the pommel. The cross or cross-guard is of square section, about 18–20 centimetres (7.1–7.9 in), tapering towards the tips,[clarification needed] in some rare cases slightly curved.[which?] The type X is narrower and longer than the typical Viking sword, representing a transitional type to the knightly sword of the High Middle Ages. Tenth century Norsemen referred to this type of sword as gaddhjalt (meaning spike hilt), this referring to the strong taper of the tang, not any visible characteristic of the pommel. The pommel usually takes an oval Brazil-nut form or a disk-shape. The inlaid ULFBERHT mark is characteristic of the type X sword.
In 1981 Oakeshott introduced the a subtype Xa including swords with similar blades but narrower fuller, originally classified under type XI.
Tapering point, in use c. 1100–1175. Features a short grip similar to type X but a distinctively longer, more slender blade suitable for slashing from horseback. Typically presents a narrower fuller than type X. Often features an acute point but generally too flexible for effective thrusting. Subtype XIa has a broader, shorter blade.
Typical of the High Middle Ages, these swords begin to show a tapering of the blade with a shortened fuller, resulting in improved thrusting characteristics while maintaining good cutting capabilities.The Cawood sword is an exceptionally well preserved specimen of type XII, exemplifying the characteristics of a taper along the full length, and narrow fuller terminating 2/3 down the blade. A large number of Medieval examples of this type survive. It certainly existed in the later 13th century, and perhaps considerably earlier, since the Swiss National Museum in Zurich possesses an example that has a Viking Age-type hilt but clearly a type XII blade. The subtype XIIa (originally classified as XIIIa) consists of the longer, more massive greatswords that appear in the mid-13th century, probably designed to counter the improved mail armour of the time, and the predecessor of the later longswords. The earliest known depiction of a type XII sword in art can be seen in the statue of the Archangel Michael in Bamberg Cathedral dating to c. 1200. The Maciejowski Bible (c. 1245) depicts other examples.
Single-handed transitional type XII swords have a grip about 4.5 inches (11 cm) in length.
Type XIIa has a long grip similar to that of XIIIa. The XIIa was originally a part of the XIIIa classification, but Oakeshott decided they "taper[ed] too strongly" and were "too acutely pointed" to fit appropriately.
This typifies the classical knightly sword that developed during the age of the Crusades. Typically, examples date to the second half of the 13th century. Type XIII swords feature as a defining characteristic a long, wide blade with parallel edges, ending in a rounded or spatulate tip. The blade cross section has the shape of a lens. The grips, longer than in the earlier types, typically some 15 cm (almost 6 inches), allow occasional two-handed use. The cross-guards are usually straight, and the pommels Brazil-nut or disk-shaped (Oakeshott pommel types D, E and I).
Subtype XIIIa features longer blades and grips. They correspond to the knightly greatswords, or Grans espées d'Allemagne, appearing frequently in 14th century German, but also in Spanish and English art. Early examples of the type appear in the 12th century, and it remained popular until the 15th century. Subtype XIIIb describes smaller single-handed swords of similar shape.
Very few examples of the parent type XIII exist, while more examples of the subtype XIIIa survive. A depiction of two-handed use appears in the Tenison(Alphonso) psalter. Another depiction of the type appears in the Apocalypse of St. John manuscript of c. 1300.
The "greatsword", within the context of the late medieval longsword, is a type of "outsize(d) specimen", specifically the Type XIIIa. The weapons were referred to by a variety of names, as in Grans espées d'Allemagne or "big swords of Germany".
The larger subtype XIIIa sword has a grip approximately 6.5–9 in (17–23 cm) long.
Ewart Oakeshott describes swords of Type XIV classification as "...short, broad and sharply-pointed blade, tapering strongly from the hilt, of flat section (the point end of the blade may, in some examples, have a slight though perceptible mid-rib, with a fuller running about half, or a little over, of its length. This may be single and quite broad or multiple and narrow. The grip is generally short (average 3.75") though some as long as 4.5"; the tang is thick and parallel-sided, often with the fuller extending half-way up it(the tang). The pommel is always of "wheel" form, sometimes very wide and flat. The cross is generally rather long and curved (very rarely straight)." Eight of the nine examples Oakeshott provided of type XIV in Records of the Medieval Sword have the distinct blade profile of a very acute triangle, with only one specimen showing an accelerating taper toward the end of the blade.
Straight tapering blade with diamond cross-section and a sharp point. Type XVa have longer, narrower blades and grips sufficiently long for two-handed use. In contrast to type XIV, these are more greatly designed for thrusting above cleaving, their appearance coinciding with the rise of plate armor. However, blades of similar cross-section and profile can be found well before the Middle-Ages and after, meaning this blade form should not soley be assigned the purpose of defeating plate armor. Many Type XV fall within the terminology of swords commonly called "bastard" or "hand-and-a-half swords" in reference to the longer grips that allowed both one and two handed use, though swords with grips of only around 5 inches would not be considered among these.
A flat cutting blade which steadily tapers to an acute point reinforced by a clearly defined ridge, making it equally effective for thrusting. This type somewhat resembles a more slender version of type XIV. These swords appear in the contemporary artwork of San Gimignano and many other works. Blade length c. 70–80cm. Subtype XVIa have a longer blade with a shorter fuller (usually running down 1/3 and rarely exceeding 1/2 of the blade). The grip is often extended to accommodate one and a half or two hands.
Characterized by a long, evenly tapering blade, hexagonal cross section, two-handed grip. Stiff, and suited toward thrusting. Oakeshott found some to be heavy swords, some examples weighing more than 2 kg, used for combat against armoured opponents. Some of these blades however were light-weight, including a sword that Oakeshott studied at the Fitzwilliam museum of Cambridge. In use c. 1360–1420.
Tapering blades with broad base, short grip, diamond cross-section. In distinction from type XV, these blades almost always feature a raised mid-rib reinforcing the blade for thrusting, and in the examples of The Records of the Medieval Sword, can be seen to have a less linear and constistent taper along the edge of the blade, sometime showing a subtle acceleration of the taper toward the very tip of the blade.  The subtype XVIIIa have narrow blades with a longer grip. Subtype XVIIIb are Bastard swords, have a longer blade and long grip and were in use c. 1450–1520. Subtype XVIIIc: shorter grip, broad blade of c. 90
15th century swords, often for one-handed use though two-handed examples exist, with relatively narrow flat blades of hexagonal cross-section, nearly parallel edges (little profile taper), narrow fullers, and a pronounced ricasso. This ricasso often presents an area of increased decoration. Additionally, several of these blades bear Arabic inscriptions and finger loops below the crossguard. 
14th to 15th century "hand and a half" or "two-handed" swords, often with two or more fullers, sometimes reducing to one fuller partway down the blade. The edges of these blades are nearly parallel or only slightly tapered until reaching a final slope to a point. These are Bastard swords, and nearly always have a hand-and-a-half grip or Two-handed swords, with room for two hands. Subtype XXa have narrower blades with a more acute and linear taper, though these can still be distinguished in part by their multiple fullers.  
Broad heavily tapering swords, similar to the fashionable Italian civilian Cinquedea of the late 15th century. Usually longer and less broad than the Cinquedea. Commonly presents with two or more fullers that continue nearly the full length of the blade. Also usually features downward (toward the blade) curved cross (quillions). The distinction away from an Cinquedea is largely based on size alone. A variation of the classic Cinquedea grip is not uncommon, though many have grips are more conventional to other European swords of the time period. 
Broad flat blades, some sharing a moderate to heavy taper with Type XXII though not as heavily or consistently. These are often flat/spatulate in cross section with the exception of 1-2 narrow fullers that only extend a short distance beyond the handle. The proportions, history of surviving examples, an often ornate decoration indicate these may have mostly served a ceremonial role more than as weapons of war. Mid 1400's-1500's.
- Oakeshott, Ewart. The Sword in the Age of Chivalry. Boydell Press 1994. Page 19.
- Oakeshott, Ewart. Records of the Medieval Sword. Boydell Press 1991. Page 72.
- Oakeshott, Ewart. The Sword in the Age of Chivalry. Boydell Press 1994. Page 37.
- Oakeshott, Ewart. Records of the Medieval Sword. Boydell Press 1991. Page 89.
- Oakeshott, Ewart. The Sword in the Age of Chivalry. Boydell Press 1994. Page 43.
- Oakeshott, Ewart. The Sword in the Age of Chivalry. Boydell Press 1994. Page 42.
- Oakeshott, Ewart. Records of the Medieval Sword. Boydell Press 2015. Page 133.
- Oakeshott, Ewart. The Sword in the Age of Chivalry. Boydell Press 1994. Page 309.
- Oakeshott, Ewart. Records of the Medieval Sword. Boydell Press 2015. Page 162.
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- Oakeshott, Ewart. Records of the Medieval Sword. Boydell Press 2015. Page 202.
- Oakeshott, Ewart. Records of the Medieval Sword. Boydell Press 2015. Page 212.
- Arrow, Chad. "Spotlight: Spotlight: Oakeshott Type XX Swords". Myarmoury. Retrieved 31 August 2018. line feed character in
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- Arrow, Chad. "Spotlight: Oakeshott Type XXI and XXII Swords". Myarmoury. Retrieved 28 July 2018.
- Arrow, Chad. "Spotlight: Oakeshott Type XXI and XXII Swords". Myarmoury. Retrieved 28 July 2018.