Beltramino Parravicini was born probably in Milan at the end of the thirteenth century, son of Stefano da Casiglio, nobilis vir and citizen of Milan, as well as holder of a significant property in Carcano (and in particular, within that parish, in Casiglio), center located in the Pieve di Incino district, near Erba, and belonging to the Ambrosian archdiocese.
Parravicini had to be trained in Milan, perhaps at the Dominican Studium of S. Eustorgio (he always showed a particular familiarity with the Order of Preachers). Close to the archbishop Cassone and to the Torriani, he evidently associated theological formation with important juridical studies, which led him to obtain both the title of magister (obtained before 1318) and important positions at the service of the papal Curia: soon entered, at least from the 1316, in the family of cardinal Giacomo Colonna, became capellanus and auditor and securely covered the function of advocatus in Roman curia from 1324 - for a long time, as specified in the will - until becoming auditor litterarum contradictarum. The assiduous presence at the Curia of Avignon and the consequent closeness to the popes determined a rapid accumulation of important prebends, as well as a favorable papal predisposition towards the Parravicini family. If at first, until the end of the Twenties, the benefits conferred sub expectantia praebendarum concentrated mainly in the diocese of origin and in the neighboring ones (archpriest of St. George of Cornate, canonicates in the collegiate church of S. Maria di Gallarate and S. Eufemia d'Incino, as well as in the cathedrals of Como, Milan and Bergamo), in the first half of the thirties concerned exclusively the French area: Parravicini in fact achieved in those years, mainly spent in Avignon, a canon in the cathedral of Reims (1330-33) and a similar benefit, with an attached cantor's dignity, in that of Bordeaux (1335).
On December 2, 1336, Benedict XII appointed him bishop of Chieti, granting him the faculty to receive so much consecration (which took place in the first half of 1338, since episcopus was defined for the first time in a papal letter of 20 June of that year , and not simply electus) as the sacred orders, including the minor ones, from whatever antistite had chosen. The consecration, whose term was repeatedly extended by the pope, occurred with considerable delay probably due to the prolongation, starting from January 1337, of a legation conducted in Spain as papal nuncio to bring peace to the kings Alfonso XI of Castile and Pietro IV of Aragon, as well as to quell contrasts intestines to the family and the Aragonese crown. The positive developments of the diplomatic mission, carried out in close and repeated contact with the pontiff, strengthened the trust and esteem of Benedict XII for Parravicini, to whom he later reassigned similar positions. Witness to the great consideration of which the bishop of Chieti enjoyed with Pope Fournier is a letter of direct consent to the King of Naples Robert of Anjou in August 1339 in anticipation of the arrival of Parravicini, after a period of stay at the Curia, in diocese of Abruzzo; a few months later (November 24), however, Benedict XII moved it from the Theatine headquarters to that of Como, where it only entered the fall of 1340.
Before that the bishop was again engaged in a delicate mission as apostolic nuncio (pro arduis negotiis, according to the definition of the pontiff himself) to recover to the Church the city of Bologna, now governed - after the expulsion of the papal legate Bertrando del Poggetto - by Taddeo Pepoli: Beltramino Parravicini formally took possession of the city in the name of the Pope in August 1340, conceding the vicariate to the lord of Felsina. Precisely on that occasion the chapters of reconciliation in the Council of the People and Parravicini were ratified, even for a short time, he exercised the functions of the podestarili. Evidently in order to consolidate the agreement reached, a short distance from it (6 November) Benedict XII again transferred the bishop from the diocese of Como to that of Bologna.
Similarly to what happened in the previous assignments, Parravicini did not reside - except for a very short time - at the office of his office (he entered the city only on 1 August 1344), entrusting the effective government of the diocese to men of close trust: in particular, the reference goes to two vicars, Paolo da Carapelle (who had at his side in each of the episcopal experiences) and Oldrado Maineri (future bishop of Novara and nephew of Parravicini).
The Milanese ecclesiastical continued in the early forties an intense diplomatic activity: after a mission to Romans, in Dauphine, carried out in the spring of 1342, he was commissioned by the newly elected Clement VI of a long, but unsuccessful, legation in Flanders, whose centers principal and its inhabitants had been struck by interdict and excommunication for having failed in the agreements signed with the king of France Philip VI. Between 1344 and 1346 he was instead engaged as an apostolic nuncio in northern Italy succeeding in obtaining that a biennial truce was respected among the main protagonists of the political scene. The legation had to take place in two separate phases, because between February and May 1345 Parravicini was again in Avignon. Because of the precarious physical conditions, which prevented him from moving from the Curia in March 1349, it was not possible for him to carry out a further diplomatic mission for which he had been designated by the Pope in order to induce the King of England Edward III to peace with the homologue of France, Philip VI, in an attempt to put an end to what will be remembered as the Hundred Years War.
The previous year (13 March 1348), when he was already in Avignon, the prelate had written a long will (published by Francesco Fossati in 1888), in which several codes are mentioned, mostly legal: among the designated testamentary executors he also figures, with specific competences regarding the provisions concerning Bologna, the great canonist Giovanni d'Andrea. Probably hit by the plague, Beltramino Parravicini died in Avignon on 7 August 1350. His body was later transferred to the burial in the church of S. Maria Assunta di Casiglio (locality of the family).