The rondel dagger was a late medieval sidearm with disc-like fittings, often associated with knights, men-at-arms, and armored close combat.
The rondel dagger is the armour-fighting dagger of the later Middle Ages: a stiff, sharply tapering blade between two discs, one serving as guard and one as pommel. It appears in the fourteenth century and remains in use into the sixteenth.
It exists because of plate armour. As harness closed off the body, the decisive weapon became the one that could be driven into the gaps that remained — the visor, the armpit, the groin, the back of the knee — and the rondel dagger is that weapon.
It was carried by men-at-arms as a matter of course and by civilians as everyday wear, so it turns up in both military and domestic contexts, and in wills and inventories as often as in battle accounts.
The blade runs roughly 25 to 40 centimetres and is built for rigidity rather than cutting: usually of triangular, diamond or square section, thick at the base and tapering to a needle point. Many examples have no cutting edge worth the name at all.
The two discs give the weapon its name and its function. The lower disc keeps the hand from sliding onto the blade under a hard thrust; the upper disc lets the wearer put his palm against the pommel and drive with the weight of his body behind it.
Construction is plain and strong. Grips are wood, bone or horn between the discs, and the whole assembly is built to survive being hammered into steel — which is why surviving examples are so often intact when more elegant weapons are not.
It is the finishing weapon of armoured combat. The fifteenth-century fight books treat armoured fighting as a wrestling problem: bring the man down, control him, and put the dagger through a gap. Fiore dei Liberi and the German masters after him all teach it the same way.
That is a grim and entirely ordinary part of a medieval battle. After the Battle of Agincourt in 1415 the French men-at-arms who fell in the mud and could not rise were killed on the ground, and this is the weapon that did it.
It also did quieter work. As civilian wear it was a self-defence weapon and, being worn at the hip in ordinary dress, appears repeatedly in accounts of murders and brawls where no armour was involved at all.
Its strength is penetration. A stiff point driven with the shoulder behind it will find and pass a mail gusset or a joint gap in plate, which nothing else in the armoury does reliably at close quarters.
Its weakness is that it needs contact. The rondel dagger is useless at any distance, so it only becomes relevant once grappling has begun — it is the last step of a sequence, never the opening.
It is also poor at everything else. With little or no edge it does not cut, it cannot parry a real weapon, and outside the specific problem of an armoured opponent at arm's length it is worse than an ordinary knife.
It emerges in the second half of the fourteenth century, in step with the spread of plate defences over mail, and its appearance is one of the clearest cases of a weapon invented for a problem that did not previously exist.
Through the fifteenth century it becomes standard equipment for the armoured man, hung at the right hip and shown on effigies and brasses across Europe as part of the complete harness.
It persists into the sixteenth century, then fades with the harness that justified it, though its logic survives in the stiletto — a narrow, edgeless thrusting dagger built on exactly the same reasoning.
The type is remarkably uniform across Europe, which is unusual and reflects a design driven by a single mechanical requirement rather than by fashion.
What varies is finish. Plain iron and wood examples sit alongside pieces with ivory grips, engraved discs and gilded mounts, and the difference is entirely social — the working parts are identical.
Related forms shade into it at the edges: the bollock dagger and the ballock-hilted knife carry similar stiff blades on quite different hilts, and contemporary vocabulary does not draw the lines modern collectors do.