[4] Rose was not yet 10 years old when the Blessed Virgin Mary is said to have instructed her to take the habit of the Third Order of St. Francis and to preach penance in Viterbo, at that time under the rule of Frederick II, Holy Roman Emperor.

When she was 12, she began preaching a message in the streets allied with Guelph aspirations,[6] thus against Emperor Frederick's rule over Viterbo.

[1] Rose wished to enter the Poor Clares of St Mary in the city, but was refused because of her poverty, as she was not able to provide the dowry required for admission.

Originally buried in the small parish church of Santa Maria in Poggio located in Piazza della Crocetta in central Viterbo; in 1257 Pope Alexander IV ordered it moved to the monastery she had desired to enter, located a few hundred meters away from her original burial, at which time it was renamed in her honor.

[8] When the liturgical calendar of the Roman Catholic Church was reformed after the Second Vatican Council, her feast day was transferred to the date of her death.

On September 3, the eve of the feast of St. Rose, the people of Viterbo follow the transportation of La Macchina ("the Machine of St. Rose") a massive 28-metre-high (92 ft) tower, illuminated with 3,000 tiny electric lights and 880 candles, and topped off with a statue of her, which is carried for 1,200 metres through the darkened streets of the old medieval town on the backs of around 100 volunteers called "facchini".

[9] St. Rose of Viterbo Convent, named for her, in La Crosse, Wisconsin, is the motherhouse of the Franciscan Sisters of Perpetual Adoration.