After graduating from the University of Bari in Alessandro Pratesi in 1961 he taught first palaeography and diplomatics in Bari, 1975, he was nominated for a Latin paleography at the Scuola Speciale per Archivisti e Bibliotecari in Rome, in 1978, he took over the chair of Greek palaeography at the Sapienza. His main areas of research are the history of transmission of the classical authors, next to the reciprocal influences of different writing systems in the mixed-language areas in the south of Italy. An example of this are the Exultet roles.
With Giovanna Nicolaj he has established a second series of Chartae Latinae Antiquiores should present the documents of the ninth century, first from Italian archives. The series begins with Volume 50, published in 1997, documents from the Archives of the Abbey of Cava de ' Tirreni contains (three volumes). More extensive stocks originate from the State Archives of Siena (3 volumes), Piacenza (8 volumes) and the archiepiscopal archives of Lucca ( 11 volumes ). Volumes 100-106, published 2006-2013, containing records of the pin Archives St. Gallen.
Since 2002, Cavallo socio nazionale of the Accademia dei Lincei, where he is also a member of the Commission for the national edition of the Greek and Latin classics. The Accademia delle Scienze di Torino He joined in 1996 as a corresponding member. He is also a member of the Comité International de Paléographie Grecque ( CIPG ) and the Comité international de Paléographie latine ( CIPL ). He is also an honorary member of the Società di Storia Patria per la Puglia.
Medaglia d' oro ai 1995 benemeriti della cultura e dell'arte, he was awarded, he was appointed Ufficiale Order of Merit of the Italian Republic in 1999.
- Pregare nel segreto: libri d' ore e testi di spiritualità nella tradizione cristiana. Direzione scientifica Guglielmo Cavallo. . - Roma: De Luca, 1994 - xviii, 204 pp. ( Catalogue of an exhibition at the Biblioteca Vallicelliana; Information)
- Epigrafia medievale Greca e Latina. Ideologia e funzione. Atti del Seminario di Erice ( Tp) (12-18 settembre 1991), a cura di Guglielmo Cavallo e Cyril Mango, Spoleto 1995 ISBN 88-7988 - 445- X
- La cultura italo - Greca nella produzione libraria. In: AA.VV.: I Bizantini in Italia. Libri Scheiwiller, Milano 1982, p 495-612 ( online at Scribd. )