The destruction of the Temple by Philip IV of France completely (or almost) destroyed everything that is the “sphragistics” of the Templar seals.
Of all the Templar sphragistics, the few seals that have come down to us are archived, mostly, in the papers of the Order of Malta (the then Hospitaller Order of Saint John of Jerusalem)
We have some examples and an accurate description in Giacomo Carlo Bascapè’s book: Sigillografia. The seal in diplomacy, in law, in history, in art – volume I, volume II Giuffrè, Milan 1969-1978.
In the chapter XX, page. 259 there is the Seal of Pierre de Montaigu, ( link to the book from the Cultural Heritage website )
Here is the interesting excerpt (pages 260-267)
II. Seals of the Templars.
The archives of the order of the Temple were lost at the time of the suppression; a small part of the documentary material, which flowed to the order of San Giovanni, is found in the magistral archive in Malta, 18 fragments of cartulares exist in some commanderies of San Giovanni, to which those of the Templars were added in the 14th century. Therefore the study of the sphragistics of the Temple militia must be limited to a series of observations, based on the few surviving examples.
There are models with the representation of the Temple of Jerusalem, equestrian types, symbolic and allegorical types, heraldic types, finally a composite model; there is therefore greater variety than in the sphragistics of the Giovannite order.
The type that was most immediately evident was, obviously, the one with the design of the sacred building from which the association took its name. It is therefore a seal, but it could also be classified among the types. Three models are known. The first, applied to documents from 1171 onwards, is crudely engraved; the legend says: ✠ MILITIA TEMPLI SAL[OMONIS]; a similar example instead has the words: ✠ SIGIllUM MILITUM TEMPLI.

In the leaden bull two types are united: on the recto two armed Templars, on a single horse; on the reverse the monument; the legend of the recto
✠ SIGILLUM MILITUM continues on the back: ✠ DE TEMPLO CHRISTI. 20 It also happened that the two tipads were impressed on two different wax “washers” affixed separately to the same document (for example the one cited from 1255).
There are three models of the Templar equestrian seals. The first, mentioned, with the two knights, is found imprinted in wax or lead on deeds from II90 onwards; in some documents it is called “sigillum consuetum”. The curious depiction (unique in the sphragistic field) has given rise to various hypotheses: De Wailly wanted to see in it the symbol of the poverty of the order in the period of its origins, but more acutely De Mas-Latrie found the allegory in it. of the brotherhood of the Templars, to whom the Rule established the obligation to always go or stay in pairs to preserve the spirit of harmony. 21
This type and the one with the Temple were the seals of the central authorities of the order; instead the institutions scattered across various places in Europe (the “nations”, the “provinces”, the commanderies, the preceptories, and even the knights) freely chose emblems, figures and deeds for their seals.
The master of Aragon and Catalonia in 1247 had a shelter with an armed knight, with a crusader shield, on a galloping horse; this model, as we know, was very widespread among nobles and knights.
An uncommon seal belonged to a French preceptor in 1255: it does not represent a soldier on horseback, but rather the patron saint of chivalry, Saint George, in the act of piercing the dragon; behind the saint there is a star; the epigraph is missing. The design recalls engraved gems and some contemporary coins, but the carving is not very successful.
Among the sacred symbols the first is the cross. A cross with slightly patent extremities is in the mark of the commendation of Alf.ambra {Spain) 1248; a contemporary type, in Gardeny, has the cross accompanied in the 1st quarter (and, apparently, in the 4th) with an eight-pointed star; in the 2nd and 3rd year crusader shield. In the French typari we find, in addition to the patent cross – simple or with a pointed lower foot – the lily cross (for example in the counterseal of the Commander of Paris, from 1290 onwards).
In that of the commandery of Aquitaine, 1251, the upper arm of the cross is fleur-de-lis, the two lateral ones are patent, the lower one is pointed.
The Agnus Dei marks the seal of the preceptory of Provence and Aragon, in 1224; a chaplain of the order in the 13th century adopted an ogival shelter (perhaps the only one of this shape, in the sphragistics of the Templars) with the scene of the pelican feeding his three young ones, while a snake threatens them; legend: ✠ S. FRATRIS PELLICERII CAPELLANI MILICIE TEMPLI. (The symbol speaks).
Among the profane symbols, those of some Spanish commanderies of the 14th century, which feature three-towered castles, deserve mention; in one case the central tower carries a crusader shield.
The most curious examples are the engraved stones of oriental origin. The preceptor of the Templars in France used an ancient oval amulet, depicting an Abraxas, as a counterseal in 1214; the gem, as usual, had been mounted in a setting, on which the words: SECRETUM TEMPLI were engraved. And Brother Aimone in 1222 used a classical carved stone with figures of fauns.
A small, personal, heraldic counterseal is impressed on the reverse of the seal of the order, hanging from. nn act of 1286; it is oval, shows a rampant lion and the legend: ✠ S. FRATRIS G. BELLI IOCI (Guglielmo di Beaujeu, alto dignitario). Eccezionalmente si trova il sigillo-ritratto, nei marchi di Simone, Commendatore di Parigi nel 1242, di Pierre le Norman, precettore di Laon nel 1282, e di Remon du Temple, Macon, 1372.
Passiamo al tipo composito, di maggiori dimensioni (da mm. 35 a 48, nei diversi modelli), usato dalla comm enda di Parigi: nel mezzo sta un’alta crocewith the three upper arms gilded, the lower arm is planted in a base; on the right is the Commander, in his conventual habit, on his knees, on the left stands a castle with three towers, which recalls, as in the Spanish essays, its military function. With variations of that type, I was used from the 13th to the 15th century. (It should be noted that the suppression of the Templars and the aggregation of many of their Commanderies to the Giovannites, the old seals of the Temple remained in use for a long time, with the inscriptions unchanged)
The seal ring of the Master General (or Bernard-Raymond Fabré-Palaprat)

The ring is that of Bernard-Raymond Fabré-Palaprat, with the 9-ball crown on it (they were Conti)
At the base of the ring, perpendicular to the Crown, there are two Knights on Horseback.
The little hearts found on the edge of the ring are the General Masters who have succeeded one another in the Clandestine from 1314 to 1804.
In the center of the ring is the Temple.
On the edges of the Temple there are two Acacia leaves which indicates clandestineness after, as previously mentioned, the Templars had entered the Consortium of Stonemasons (or Freemasonry)
This ring is the one given by Napoleon Bonaparte to the First Master General of the Sovereign Military Order of the Temple of Jerusalem, and has then passed from Master to Master over the years.