Francesco Rugeri (c.1628-1698) has traditionally been considered the earliest student of Nicolò Amati as well as the best imitator of Amati, as his works follow Amati closely. Most of his works were made in 1660s-90s, of which the most prolific period was the 1670s-80s when his four sons assisted him in the family workshop. He gave his violin a full arching and a widened body and attempted to enhance its playing quality to be more powerful, bright and deep. He tended to use orange varnish in early stage and red-brown or dark red varnish in late period. Francesco Rugeri left a substantial impact on 18th-century luthiers including Stradivari, whose early works displace stylistic and technical similarities, and Carlo Bergonzi who is very likely to be the student of Francesco's son Vincenzo Rugeri.
The largest impact Rugeri made historically was his experimentation with smaller cello models, 20 years earlier before Stradivari and Andrea Guarneri began to move away from the large cello designs typical of the period. He was the first luthier of the Cremonese school to develop the smaller cello model, which later became the universally accepted cello size. Rugeri's cellos are highly regarded today.
The violin made by Francesco Rugeri in 1684 is the oldest instrument in the collection of the Yu Art Foundation. While Amati's dominance in the 17th-century Cremonese violin making scene kept his rivals at bay during his lifetime, today Rugeri's instruments are nearly as renowned as Amati's.