I'm trying to research the types of armor and weaponry that an English man-at-arms would use at Agincourt. I would mostly like to know whether there was a preference in the types of swords used.
Thank you all in advance.
English fighting was primarily designed for 'foot' combat, favoriting twohanded weapons, such as spears, pollaxes, and great-swords. As such the armor that they wore developed to accommodate these preferences for fighting, showing distinctions from continental armors such as completely enclosed upper arm and upper leg protection.
With heavy plates, articulated on leather straps (on the inside of successive lames) the gaps in the large plates would then be protected by chain (mail) armor voiders. This heavy armor configuration again allows a tremendous amount of protection while still giving the fighting man very good mobility on foot for combat.
Foremost researcher on the development of English armor, Dr. Tobias Capwell writes about the following developments specific to the period around Agincourt.
A fundamental innovation moving into the second decade of the fifteenth century is the fully-fledged great basicnet, having solid collar plates in the front and rear. The great bascient is at this stage strapped down to the cuirass at the back but not at the front. An inner chin plate protects the chin and cheeks under the front collar plate. Mail continues to cover the area formerly protected by the aventail, but is now worn as a standard or 'pisan'.
The soild one piece Backplate is now married to a solid backplate [Cuirass] often made in three pieces, a development of earlier hinged reredos' designs. The kidney-plates have been riveted to a narrower spine-lame, instead of strapped down the center of the back. The solid backplate is hinged to the breastplate on the left side, and strapped closed on the right so that it can be opened to accept the wearer's body. The cuirass skirt, continuing to be worn as a separate element often remains hinged on both sides and fastened own the back in the manner of earlier designs.
This configuration of armor can be seen on the effigy of William Wilcote in St. Mary's Chruch, dated to about 1411
https://www.flickr.com/photos/52219527@N00/2423373200/in/photostream/
As to the swords in use of at the period (pedantic note; in period all of these anachronistic classifications would have been moot. They would likely have just been called 'sword' regardless of their configuration), there may have been some continued late usage of Oakeshott type XV, XVa, and XVII blades, while types XVIII, sub types XVIIIa-e, and type XIX should have all been in use at this time.
https://en.wikipedia.org/wiki/Oakeshott_typology
Most swords would be single handed in use to allow for shield use in the off hand ("arming swords" conventionally today), and as previously mentioned the heavy configurations of armor did allow for two handed swords to be brought to bear as well. This is depicted here in the contemporaneous English Troy Book manuscript.
https://www.digitalcollections.manchester.ac.uk/view/MS-ENGLISH-00001/277
As far as specific examples of sword types in use, in 2015 Wallace Collection organized a display called The Sinews of War: Arms and Armour from the Age of Agincourt
For this display it in particularly highlighted these swords as examples of what might have been in use by the combatants at Agincourt:
Sword A460
Some 95.4 cm long. A handsome type XV arming sword, it has a wheel pommel (form L), and curved down quillons (cross style 9). There are remnants of copper inlay markings on the blade.
Sword A474
A large two handed sword which has a blade alone measuring 1.17meters.
Sword A465
A very narrow type XV single handed sword, showing a very wide guard. Only 87.3 cm in length, but optimized for thrusting.
Ref:
Tobias Capwell Armour of the English Knight 1400-1450
Ewart Oakeshott The Sword in the Age of Chivalry