The papal Sphragistics essentially differentiates two customs in the document sealing procedures: the usage of the leaden bull (or seldom a gold one) on one hand and the usage of a wax seal or a anulus piscatoris on the other. In the first case we have a pending seal, in the second an adherent one.
The bull, pending from great and solemn privileges as from simpler letters or mandates, is one of the most important diplomatic elements of papal documents so that the term is used to indicate all the papal documents which are provided with this particular kind of seal. From an iconographical point of view, papal bulls, starting from Pasquale II (1099-1118) maintain an unchanged formal identity in the constituent scheme, until nowadays. This expressive rigidity, even with the unavoidable variations due to the artistic taste of different periods, is meant to express by means of a permanent image, the continuity of the Church, founded by the Apostles, throughout the centuries. The two sides of the bull show, on the recto, Paul and Peter’s heads with the writing S(anctus) PA(ulus)/S(anctus) PE(trus), and on the verso, the pope’s name, the title and the ordinal number of succession. The faces of the Apostles, plastically characterized, are portrayed with a fluent hair and beard for St. Paul and with a curled and short beard for St. Peter. Before pope Pasquale II, the iconography presents some variations which range from simple onomastic models to more articulated characterizations. From a technical point of view, the bull was created with the impression of leaden round with metallic matrixes, assembled on a tongs tool, which was then replaced with bigger vices. The pressure on the lead, which squashed the metal, thus leaving its imprint on it, imprisoned the hanging thread which was then introduced into a hole previously made in the lead.
Every time a pope dies, the matrix with his name is destroyed, whereas the one with the Apostles’ images is used again by his successor or replaced only if it was damaged. If the new elected pope needed to draw up some documents in the period between the election and the crowning, he could use the so-called bulla dimidia, which was impressed only on the side with the heads of the Apostles and smooth on the other. This because only after the crowning, once the pope had adopted his papal name, he could order to have it carved on the matrix. A proper formula explains this custom in the eschatocol of the document.
The adherent red wax seal, protected by a parchment plait or by some little tin caskets, is the so called anulus piscatoris. This kind of seal, together with other diplomatic elements, identifies a particular category of documents issued by the papal chancery, the so-called briefs. The size of this oval seal is small (two or three cm for each axis); it adhered to the document thanks to two slits made on the writing medium, through which, in any case, a little strip of parchment was passed. The iconographical detail of the anulus piscatoris shows St. Peter on a boat, pulling up the fishing nets and a legend with the name of the pope and the ordinal number. The wax papal seal is announced in the datary of the document with the formulas: …sub anulo piscatoris or…sub anulo fluctuantis naviculae… The pope could also use his private (or secret) seal for particular kinds of letters, that is a simple anepigraphic wax seal with the representation of his coat of arms.
From the second half of the 19
th Century, papal seals on the documents were replaced with a stamp, the modern heir of the sphragistic custom, which reproduces the images of the seals, although the bull is still used today for very important papal documents.
