Giacomo Rossi was an Italian 'poet', translator and librettist who settled in London early in the 18th century and wrote librettos for George Frideric Handel

George Frideric Handel

George Frideric Handel was a German-British Baroque composer, famous for his operas, oratorios, anthems and organ concertos. Handel was born in 1685, in a family indifferent to music...

, between 1710 and 1729.

According to Rossi Rinaldo (opera)

Rinaldo (opera)

Rinaldo is an opera by George Frideric Handel composed in 1711. It is the first Italian language opera written specifically for the London stage. The libretto was prepared by Giacomo Rossi from a scenario provided by Aaron Hill. The work was first performed at the Queen's Theatre in London's...

 was written by Handel in a fortnight. Aaron Hill

Aaron Hill

Aaron Hill was an English dramatist and miscellaneous writer.The son of a country gentleman of Wiltshire, Hill was educated at Westminster School, and afterwards travelled in the East. He was the author of 17 plays, some of them, such as his versions of Voltaire's Zaire and Mérope, being adaptations...

 seems to have given his sketch to Rossi to translate. The libretto is according to Winton Dean

Winton Dean

Winton Dean is an English musicologist of the 20th century, most famous for his research concerning the life and works—in particular the operas and oratorios—of Handel, as detailed in his book Handel’s Dramatic Oratorios and Masques .Dean was born in Birkenhead...

 confusing.

Rossi probably worked on Il pastor fido (Handel) and Silla (opera)

Silla (opera)

Silla is an opera seria in three acts by George Frideric Handel. The Italian-language libretto was by Giacomo Rossi. The story concerns the Roman general Lucius Cornelius Sulla as recounted by Plutarch.The opera appears to have been a pièce d'occasion, whicht may have been performed only once...

. Handel emerges from the enterprise with scarcely more credit than Rossi.

Rossi's name is also mentioned with for the libretto of Amadigi di Gaula

Amadigi di Gaula

Amadigi di Gaula is a magical opera in three acts, with music by George Frideric Handel. It was the fifth Italian opera that Handel wrote for London and was composed during his stay at Burlington House in 1715...

, or assisting in Poro re dell'Indie and Lotario

Lotario

Lotario is an opera seria in three acts written for the Royal Academy of Music by George Frideric Handel. The Italian-language libretto was adapted from Antonio Salvi's Adelaide.-Performance history:...

. The result of this latter work is unusually concise and easily understandable for a baroque opera. Rossi not only shortened the recitatives for Handel, but improved the text by shortening, rearranging and rewriting it. Almost half of the text was new.

In 1729 Paolo Antonio Rolli

Paolo Antonio Rolli

Paolo Antonio Rolli was an Italian librettist and poet.He was born in Rome, Italy and like Metastasio was trained by Gian Vincenzo Gravina. He worked in London from 1715 to 1744 where he became Italian tutor to the prince of Wales and the Royal Princesses...

 wrote: You will have heard by now that Attilio

Attilio Ariosti

Attilio Malachia Ariosti was an Italian composer in the Baroque style, born in Bologna. He produced more than 30 operas and oratorios, numerous cantatas and instrumental works.-Life:He was born into the middle class...

 and Haym

Nicola Francesco Haym

Nicola Francesco Haym was an Italian opera librettist, composer, theatre manager and performer, and numismatist. He is best remembered for adapting texts into libretti for the London operas of George Frideric Handel and Giovanni Bononcini...

 have died. I inform you now that the famed Rossi, Italian writer and poet is Handel’s librettist.

Source

• Dean, Winton; Knapp, J. Merrill
  J. Merrill Knapp
  John Merrill Knapp was an American musicologist and academic. He was considered an authority on the life and works of George Frideric Handel. Born in New York City, Knapp graduated from the Hotchkiss School before entering Yale University where he earned a Bachelor of Arts in 1936 and was a member...
  
  (1987). Handel's Operas, 1704–1726. Clarendon Press. ISBN 0193152193
• Dean, Winton (2006). Handel's Operas, 1726–1741, p. 173. The Boydell Press. ISBN 1-84383-268-2