Pietro Alessandro Gaspare Scarlatti (2 May 1660 – 22 October 1725) was an Italian Baroque composer, especially famous for his operas and chamber cantatas.
 He is considered the founder of the Neapolitan school of opera.
 He was the father of two other composers, Domenico Scarlatti and Pietro Filippo Scarlatti.
Giuseppe Domenico Scarlatti (Naples, 26 October 1685 Madrid, 23 July 1757) was an Italian composer who spent much of his life in the service of the Portuguese and Spanish royal families.
 He is classified primarily as a Baroque composer chronologically, although his music was influential in the development of the Classical style and he was one of the few Baroque composers to transition into the classical period.
 Like his renowned father Alessandro Scarlatti, he composed in a variety of musical forms, although today he is known mainly for his 555 keyboard sonatas.
Il trionfo dell'onore ("The Triumph of Honour") is an operatic 'commedia' in three acts by the Italian composer Alessandro Scarlatti, with a libretto by .
 It was first performed at the Teatro dei Fiorentini, Naples on 26 November 1718.
 It is Scarlatti's only known comic opera.
Francesco Scarlatti (5 December 1666 – c. 1741) was an Italian Baroque composer and musician and the younger brother of the better known Alessandro Scarlatti.
Il Pompeo is a dramma per musica in three acts by composer Alessandro Scarlatti.
 Written in 1682 when Scarlatti was 22 years old, it was his fourth opera and first dramatic work on a serious and grand subject.
 The opera uses an Italian language libretto by Nicolò Minato which had previously been used by Francesco Cavalli for his 1666 opera "Pompeo Magno".
 The work premiered at the Teatro di Palazzo Colonna in Rome on 25 January 1683.
Tigrane, o vero L'egual impegno d'amore e di fede ("Tigranes or The Equal Ties of Love and Faith") is an opera seria in three acts by the Italian composer Alessandro Scarlatti with a libretto by Domenico Lalli (loosely based on the "Histories" of Herodotus).
 It was first performed at the Teatro San Bartolomeo, Naples on 16 February 1715.
 It is regarded as one of Scarlatti's finest operas.
 As well as the serious main plot, there are also comic scenes involving the servants Dorilla and Orcone.
Philip Morris Glass (born January 31, 1937) is an American composer.
 He is widely regarded as one of the most influential musicians of the late 20th century.
Griselda is an opera seria in three acts by the Italian composer Alessandro Scarlatti, the last of Scarlatti’s operas to survive completely today.
 The libretto is by Apostolo Zeno, with revisions by an anonymous author.
 Zeno wrote his work in 1701 and it had already been set by Pollarolo and Antonio Maria Bononcini (Albinoni, Giovanni Bononcini and Vivaldi would later produce versions).
 It is based on the story of Patient Griselda from Boccaccio's "Decameron".
 Scarlatti's opera was first performed at the Teatro Capranica, Rome in January, 1721 with an all-male cast (five castratos and a tenor).
Il Mitridate Eupatore ("Mithridates Eupator") is an opera seria in five acts by the Italian composer Alessandro Scarlatti with a libretto by Girolamo Frigimelica Roberti.
 It was first performed at the Teatro San Giovanni Grisostomo, Venice on 5 January, 1707.
 A failure at its premiere, "Mitridate Eupatore" is now considered one of the finest of Scarlatti's operas.
L'honestà negli amori is a dramma per musica in 3 acts by composer Alessandro Scarlatti.
 Written in 1679-1680 when Scarlatti was 19 years old, it was his second opera.
 The opera uses an Italian language libretto that was written by either D F Bernini or Domenico Filippo Contini.
 The work premiered at the Teatro di Palazzo Bernini in Rome on 3 February 1680.
 The opera was performed again in 1682 in Acquaviva delle Fonti at the Palazzo De Mari with "Acquaviva laureata" a serenata composed by Giovanni Cesare Netti.

Question: Which composer is older, Alessandro Scarlatti or Philip Glass?
Answer: Pietro Alessandro Gaspare Scarlatti