Giulio Cesare Russo was born in Brindisi, Kingdom of Naples, to a family of Venetian merchants. He was educated at Saint Mark's College in Venice, and joined the Capuchins in Verona as Brother Lawrence. He received further instruction from the University of Padua. An accomplished linguist, Lawrence spoke most European and Semitic languages fluently. He was appointed definitor general to Rome for the Capuchins in 1596; Pope Clement VIII assigned him the task of converting the Jews in the city. Beginning in 1599, Lawrence established Capuchin monasteries in modern Germany and Austria, furthering the Counter-Reformation and bringing many Protestants back to the Catholic faith. In 1601, he served as the imperial chaplain for the army of Rudolph II, Holy Roman Emperor, and successfully recruited Philippe Emmanuel, Duke of Mercur to help fight against the Ottoman Turks. He then led the army during the brief liberation of Szkesfehrvr in Hungary from the Ottoman Empire, armed only with a crucifix. In 1602, he was elected vicar general of the Capuchin friars, at that time the highest office in the Order. He was elected again in 1605, but refused the office. He entered the service of the Holy See, becoming papal nuncio to Bavaria. After serving as nuncio to Spain, he retired to a monastery in 1618. He was recalled as a special envoy to the King of Spain regarding the actions of the Viceroy of Naples in 1619, and after finishing his mission, died on his birthday in Lisbon.