Bernardino degli Albizeschi was born in Massa Marittima, near Siena, Italy, on 8th September, 1380.  He was the son of the governor of Massa, but his parents died in 1386 and he was brought up with great care by his pious aunt Bartholomea.   In 1397 after a course of civil and canon law, he joined the Confraternity of Our Lady attached to the great hospital of Santa Maria della Scala. When the plague came to Siena in 1400, Bernardino offered to take charge of the hospital, gathering round him twelve young friends who were willing to risk their lives to share this duty.

 For four months, they worked tirelessly, several of them died and Bernardino never completely recovered.  After the end of the pestilence, he cared for his blind and bedridden aunt and, after her death, he prayed and fasted to learn God's will for his future. While praying before his crucifix, he was impressed and reproached, like Saint Francis, by the suffering of Our Lord,  He distributed his patrimony in charity and received the habit of the Friars Minor at San Francesco in Siena, 8th September, 1402.
In 1403  after being professed, Bernardino withdrew to the the Franciscan monastery of strict observance at Colombaio outside the city.   He was  ordained on 8th September, 1404, and, over the next 12 years, he preached only occasionally, preferring to live as a solitary.

On 8th September, 1417, he went to Milan and preached his first sermon as a missionary.  Despite being a stranger to the city, his eloquence and fiery sermons soon attracted huge congregations. He traveled throughout Italy on foot to preach in every town and village he entered. Various cities contended for the honour of hearing him, and he was often compelled to preach in the market places, because the crowds were huge.  He castigated vice and then hold up a placard with the sign of the name of Jesus, "IHS" written on it: people became so enthused that they even had these letters painted on houses. At Bologna Bernardino induced a man whose livelihood came from making playing cards, and who had been ruined by his sermons against gambling, to make a living by designing these tablets, and the man soon realized a small fortune. 

His watchword, like that of St. Francis, was "Peace", so he persuaded many cities to take down the arms of their warring factions from the church and palace walls and to inscribe there, instead, the initials "IHS".  He exercised his eloquence with great effect towards reconciling Guelphs and Ghibellines and, at Crema, the political exiles were recalled and even reinstated in their confiscated possessions.
Usury was one of the principal objects of his attacks and he prepared the way for the establishment of the beneficial loan societies, known as "Monti di Pietà".  Bernardino wrote a book devoted to economics, pointing out that trade, like all other occupations, could be practiced either lawfully or unlawfully.  Its title is "On Contracts and Usury", and it deals with the justification of private property, the ethics of trade, the determination of value and price, and the usury question.

Bernardino was accused of heresy, the tablets he had used to promote devotion to the Holy Name were made the basis of a clever attack against him, and this controversy troubled him for eight years. His detractors accused him of encouraging superstitious practices, he was charged with having introduced a profane, new devotion which exposed the people to the danger of idolatry. They said that he carried on his person a piece of paper on which the Name of Jesus was written, that when he showed it to sinners, it gave out rays of light. In 1427, he was cited to appear before Pope Martin V, who received him coldly and forbade him to preach or exhibit his tablets until his conduct had been examined.

His trial took place at St. Peter's in presence of the pope, on 8th June 1427, and St.Bernardino was defended by St.John Capistran, great jurist and governor of Perugia, who had joined the Franciscan Order when he was thirty years old and is the patron of the military chaplains (Feast: 23rd October).  Bernardino was cleared of the charges after an examination of his doctrine and conduct. The pope urged him to preach in Rome and approved his election as Bishop of Siena, but he declined this honour.  He was offered bishopric also at Ferrara in 1431 and at Urbino in 1435,  but he always refused, because he would have had to give up his primary calling, that of a missionary, and said playfully that all Italy was already his diocese.   After the accession of Pope Eugene IV, Bernardino's calumniators renewed their accusations against him, but the Pope reduced them to silence by a Bull, on 7th January 1432.

In 1430, the "Apostle of the Holy Name" became "Vicar General" of the Friars of the Strict Observance. He reformed the rule and involved the friars more as preachers and teachers, insisting upon instruction in theology and canon law as part of the regular curriculum.  Many convents passed easily from the Conventual to the Observant rule, and the number of friars grew from 300 to over 4,000.  
Bernardino wrote treatises on the Blessed Mother and theological works in Latin and Italian, covering the principal doctrinal and moral elements of Christianity.

He was the most prominent missionary of the 15th century and he is often called the "Apostle of Italy".  In 1956, he was made the patron saint of advertisers and advertising by Pope Pius XII  because of his ability to illuminate the Catholic faith to audiences by the use of the simplest and most popular language.
His sermons lasted three or four hours and abounded in illustrations, anecdotes and digressions. He adapted himself to the local dialects and parlances, and he often resorted to mimicry and jokes. In 1427, one Benedetto of Siena took down word by word forty-five Lenten sermons in vernacular.  The original manuscript is lost, but several very ancient copies of it are extant, and have been printed with the title:"Le Prediche Volgari di Siena".