He was perhaps the earliest apprentice of
Nicolò Amati, another important
luthier in
Cremona, Italy, although some sources call this association into question as there is no census record showing his presence in the Amati household. This could be explained by the possibility of Francesco living and boarding at his own home while apprenticing, rather than being an indoor apprentice.
Antonio Stradivari's name also never appears in the records, despite being another possible pupil.
W.E. Hill & Sons note that the "unmistakable" handiwork of Francesco Rugeri can be found in select pieces by Nicolo Amati and, just like Antonio Stradivari and Andrea Guarneri, Francesco sometimes included the words "Alumnus Nicolai Amati" on his labels, further adding to the evidence of his apprenticeship. For example, there exists a violin labelled "Francescus Rugerius Alumnus Nicolai Amati fecit Cremonæ 1663". Nicolò Amati was the godfather to one of Francesco's sons, Giacinto (born in 1658 and lived only a few months), indicating that the two families at least shared a close relationship and close collaboration would seem likely. Francesco later had another son whom he also named Giacinto, who was born in 1661. In 1685, a court case was brought by a violinist seeking relief from the Duke of Modena as a victim of fraud. In this case, the violinist and composer
Tomaso Antonio Vitali had bought a violin purporting to be a creation of Nicolò Amati, but he discovered that under the Amati label was the label of Francesco Rugeri. There was a price difference in those days of 3 to 1 on Amati vs. Rugeri violins, so this was a serious matter. However, this case may also indicate that Rugeri, who was working in the shadow of the great Cremona makers—Amati,
Guarneri, and Stradivari—had resorted to a desperate act to make a sale. Some researchers believe there is a closer educational association between Antonio Stradivari and Francesco Rugeri than previously thought. Despite the long-held belief that Antonio Stradivari was a pupil of Nicolò Amati, there are important discrepancies between their work. Some researchers believe early instruments by Stradivari bear a stronger resemblance to Francesco Rugeri's work than Amati's. Additionally, the use of a small dorsal pin or small hole, invariably used not just by Nicolò Amati but all of his recognized pupils—with the exception of Antonio Stradivari—adds further evidence that Stradivari may have learnt his craft apart from Amati. This pin or hole was fundamental in the graduation of the thickness of the plates, and was obviously a technique passed on through generations of pupils of the Amati. This dorsal pin is also not found in any of the instruments of the Rugeri family, suggesting Antonio Stradivari may have actually learnt his craft from Francesco Rugeri, although both being influenced by Amati. W.E. Hill & Sons concede that they fail to find the hand of Stradivari in any of Nicolo Amati's work, although the unmistakable hands of Andrea Guarneri and Francesco Rugeri are evident.
Count Ignazio Alessandro Cozio di Salabue and other early violin connoisseurs, such as the Mantegazza brothers, seemed to confuse the families of the Rugeri working in Cremona with the family of
Giovanni Battista Rogeri working in Brescia. The two families both followed the Amati tradition; however, their work is distinctive from each other and not thought to be related. The Rugeri family included the words "il Per" or "detto il Per" in their labels and, from 1669 onward, in almost all of the religious and legal documents pertaining to the family, most likely to distinguish them from the many other Rugeri families in the region. ==Career==