St. Lawrence was born in 1559 to Guglielmo de Rossi and Elisabetta Masella, who had their child baptized Julius Caesar Rossi. The boy was educated in his native Brindisi by the Friars Minor Conventuals and later studied in Venice. When Julius was twelve years old his father passed away.
Four years later, at the age of sixteen, Julius joined the Capuchin Friars and took the name of Brother Lawrence. As a young friar, Brother Lawrence continued his studies in theology along with becoming proficient in French, German, Greek, Spanish, Hebrew, and Syriac/Bohemian. After finishing his studies Brother Lawrence was ordained to the priesthood.
Now Father Lawrence travelled throughout Europe preaching the Gospel. The Capuchin was well known for being an "effective and forceful preacher." His great knowledge of languages allowed him to preach in numerous countries, taking him to such places as Vienna, Prague, and Graz where he founded convents.
In 1601, Fr. Lawrence served as chaplain of the Holy Roman Empire. Around this time the Turks mounted an invasion of Europe and Fr. Lawrence "rallied the German princes to fight." Carrying nothing but a crucifix, Fr. Lawrence led the army into battle against the superior Turkish force. The battle was won. Fr. Lawrence also served as the spiritual director of the Bavarian Army.
St. Lawrence served as master general of his order from 1602-1605 and was selected for a second term but refused.
His two great loves were the Mass and the Blessed Mother. He is known to have often "fall[en] into ecstasies when celebrating Mass," once taking sixteen hours to complete a Mass.
Fr. Lawrence was, several times, sent on peace missions, all of which were succesful. He died of natural causes while on his final peace mission to Spain. He is "buried in the cemetery of the Poor Clares on Villafranca." Pope Leo XIII canonized Fr. Lawrence on December 8, 1881 and Pope John XXIII declared him a doctor of the Church, due to his extensive writings, in 1959. St. Lawrence is the patron saint of his native home of Brindisi, Italy.