Mario Di Calasio (1550-1620), Italian Minorite friar, was born at a small town in the Abruzzi whence he took his name. Joining the Franciscans at an early age, he devoted himself to Oriental languages and became an authority on Hebrew. Coming to Rome he was appointed by Paul V., whose confessor he was, to the chair of Scripture at Ara Coeli, where he died on the 1st of February 1620. Calasio is known by his Concordantiae sacrorum Bibliorum hebraicorum, published in 4 vols. (Rome, 1622), two years after his death, a work which is based on Nathan's Hebrew Concordance (Venice, 1523). For forty years Calasio laboured on this work, and he secured the assistance of the greatest scholars of his age. The Concordance evinces great care and accuracy. All root-words are treated in alphabetical order and the whole Bible has been collated for every passage containing the word, so as to explain the original idea, which is illustrated from the cognate usages of the Chaldee, Syrian, Rabbinical Hebrew and Arabic. Calasio gives under each Hebrew word the literal Latin translation, and notes any existing differences from the Vulgate and Septuagint readings.

An incomplete English translation of the work was published in London by Romaine in 1747. Calasio also wrote a Hebrew grammar, Canones generates linguae sanctatae (Rome, 1616), and the Dictionarium hebraicum (Rome, 1617).