The signa crucis and signa tabellionis of the Tabulario of the Monasteries of San Nicolò l’Arena and Santa Maria di Licodia are a homogeneous body from which it is possible to get valuable information about the close link between the diplomatic significance of the document and the editorial one. The reviewed acts present validate parchments both with, more or less accurate, signum crucis solo or with signum crucis accompanied by signum tabellionis, aiming at ensuring the authenticity of the public act.
Keywords: signa crucis, signa tabellionum, monasteries, link, public act, authenticity.