Question: Which Italian composer was from the earliest time period, Giovanni Battista Pergolesi or Giacomo Puccini?
Context: La conversione e morte di San Guglielmo ("The Conversion and Death of Saint William") is a sacred musical drama ("dramma sacro") in three parts by the Italian composer Giovanni Battista Pergolesi.  The libretto, by Ignazio Mancini, is based on the life of Saint William of Aquitaine as recounted by Laurentius Surius.  It was Pergolesi's first operatic work, possibly written as a study exercise for his conservatory.  The work was premiered at the Monastery of Sant'Agnello Maggiore, Naples in the summer of 1731. Giovanni Battista Draghi (] ; 4 January 1710 – 16 March 1736), best known as Pergolesi (] ) or Giovanni Battista Pergolesi, was an Italian composer, violinist and organist. Il prigionier superbo ("The Proud Prisoner") is an "opera seria" in three acts composed by Giovanni Battista Pergolesi to a libretto attributed to Gennaro Antonio Federico and based on an earlier libretto by Francesco Silvani for Gasparini's opera, "La fede tradita e vendicata".  It was premiered at the Teatro San Bartolomeo in Naples on 5 September 1733 and received further performances in October.  The opera, with its labyrinthine plot involving the rivalry of Metalce (King of the Goths) and Viridate (Prince of Denmark) for the hand of Rosmene (a Norwegian princess whose father is Metalce's prisoner), soon sank into oblivion, but its comic intermezzo, "La serva padrona" (also by Pergolesi) was to achieve considerable success when performed on its own. Giacomo Antonio Domenico Michele Secondo Maria Puccini (] ; 22 December 1858 29 November 1924) was an Italian opera composer who has been called "the greatest composer of Italian opera after Verdi". Stabat Mater is a musical setting of the "Stabat Mater " sequence, composed by Giovanni Battista Pergolesi in 1736.  Composed in the final weeks of Pergolesi's life, it is scored for soprano and alto soloists, violin I and II, viola and basso continuo (cello and organ). Unico Wilhelm, Count van Wassenaer Obdam (30 October 1692 - 9 November 1766) was a Dutch nobleman who was a diplomat, composer, and administrator.  He reorganized the Bailiwick of Utrecht of the Teutonic Order.  His most important surviving compositions are the "Concerti Armonici", which until 1980 had been misattributed to the Italian composer Giovanni Battista Pergolesi (1710-1736) and to Carlo Ricciotti (1681-1756). L'Olimpiade is an opera in the form of a dramma per musica in three acts by the Italian composer Giovanni Battista Pergolesi.  Pergolesi took the text, with a few modifications, from the libretto of the same name by Pietro Metastasio.  The opera first appeared during the Carnival season of 1735 at the in Rome and "came to be probably the most admired" of the more than 50 musical settings of Metastasio’s drama. Pergolesi is a 1932 Italian historical musical film directed by Guido Brignone and starring Elio Steiner, Dria Paola and Tina Lattanzi.  It portrays the brief life of the eighteenth century Italian composer Giovanni Battista Pergolesi. Adriano in Siria is an opera by Giovanni Battista Pergolesi setting Metastasio's libretto of the same name.  It was the third of his four opere serie, premiered at Teatro San Bartolomeo in Naples on 25 October 1734.  Pergolesi also provided a comic intermezzo "La contadina astuta", later better known as "Livietta e Tracollo", to a libretto by Tomasso Mariani. Il Flaminio is a 1735 opera buffa by Giovanni Battista Pergolesi to a libretto by Gennaro Antonio Federico, first performed at the Teatro Nuovo, Naples.  Untypically in Pergolesi's difficult and short career the opera was an immediate success and continued to be staged up to 1750.
Answer: Giovanni Battista Pergolesi