Question: Who is the father of the person that developed Elephant and Obelisk?

full_context: Document 1: The Goat Amalthea with the Infant Jupiter and a Faun: The Goat Amalthea with the Infant Jupiter and a Faun is the earliest known work by the Italian artist Gian Lorenzo Bernini. Produced sometime between 1609 and 1615, the sculpture is now in the Borghese Collection at the Galleria Borghese in Rome.
Document 2: Memorial to Maria Raggi: Memorial to Maria Raggi is a sculptural monument designed and executed by the Italian artist Gian Lorenzo Bernini, in 1647. The monument is attached to a pillar in a nave of the church of Santa Maria sopra Minerva in Rome.
Document 3: Sleeping Hermaphroditus: The Sleeping Hermaphroditus is an ancient marble sculpture depicting Hermaphroditus life size. In 1620, Italian artist Gian Lorenzo Bernini sculpted the mattress upon which the statue now lies. The form is partly derived from ancient portrayals of Venus and other female nudes, and partly from contemporaneous feminised Hellenistic portrayals of Dionysus/Bacchus. It represents a subject that was much repeated in Hellenistic times and in ancient Rome, to judge from the number of versions that have survived. Discovered at Santa Maria della Vittoria, Rome, the "Sleeping Hermaphroditus" was immediately claimed by Cardinal Scipione Borghese and became part of the Borghese Collection. The "Borghese Hermaphroditus" was later sold to the occupying French and was moved to The Louvre, where it is on display.
Document 4: Bust of Gabriele Fonseca: The Bust of Gabriele Fonseca is a sculptural portrait by the Italian artist Gian Lorenzo Bernini. Executed sometime between 1668 and 1674, the work is located in San Lorenzo in Lucina in Rome, Italy. Gabriele Fonseca was the doctor to Pope Innocent X.
Document 5: Aeneas, Anchises, and Ascanius: Aeneas, Anchises, and Ascanius is a sculpture by the Italian artist Gian Lorenzo Bernini created c. 1618-19. Housed in the Galleria Borghese in Rome, the sculpture depicts a scene from the "Aeneid", where the hero Aeneas leads his family from burning Troy.
Document 6: Martyrdom of Saint Lawrence: Martyrdom of Saint Lawrence is an early sculpture by the Italian artist Gian Lorenzo Bernini. It depicts the saint at the moment of his martyrdom, being burnt alive on a gridiron. According to Bernini's biographer, Filippo Baldinucci, the sculpture was completed when Bernini was 15 years old, implying it was finished in the year 1614. Other historians have dated the sculpture between 1615 and 1618. A date of 1617 seems most likely. It is less than life-size in dimensions, measuring 108 by 66 cm.
Document 7: Elephant and Obelisk: The statue is a sculpture designed by the Italian artist Gian Lorenzo Bernini. The elephant was probably executed by his assistant Ercole Ferrata; the Egyptian obelisk was uncovered during nearby excavations. It was unveiled in February 1667 in the Piazza della Minerva in Rome, adjacent to the church of Santa Maria sopra Minerva, where it stands today.
Document 8: The Rape of Proserpina: The Rape of Proserpina () is a large Baroque marble sculptural group by Italian artist Gian Lorenzo Bernini, executed between 1621 and 1622. Bernini was only 23 years old at its completion. It depicts the Abduction of Proserpina, who is seized and taken to the underworld by the god Pluto.
Document 9: Bust of Giovanni Vigevano: Bust of Giovanni Vigevano is a marble sculptural portrait by the Italian artist Gian Lorenzo Bernini. The bust was produced between 1617 and 1618, and was then inserted into the tomb for Vigevano after he died in 1630. The tomb is in the church of Santa Maria sopra Minerva in Rome.
Document 10: Bust of Francesco Barberini: The Bust of Francesco Barberini is a marble sculpture by the Italian artist Gian Lorenzo Bernini, now in the National Gallery of Art in Washington, D.C.. It was executed in 1623. It was commissioned by Pope Urban VIII, who was nephew of Francesco Barberini, an apostolic protonotary. Francesco had actually died in 1600 so Bernini created the bust from an existing painted portrait. The painted portrait is in Corsini Collection in Florence; Bernini made close use of the design, although the painting was a three quarter portrait as opposed to a bust of head, shoulders and upper body.
Document 11: Risen Christ (Michelangelo, Santa Maria sopra Minerva): The Risen Christ, "Cristo della Minerva" in Italian, also known as "Christ the Redeemer" or "Christ Carrying the Cross", is a marble sculpture by the Italy High Renaissance master Michelangelo, finished in 1521. It is in the church of Santa Maria sopra Minerva in Rome, to the left of the main altar.
Document 12: Charity with Four Children: Charity with Four Children is a sculpture by the Italian artist Gian Lorenzo Bernini. Executed between 1627 and 1628, the work is housed in the Vatican Museums in Vatican City. The small terracotta sculpture represents "Charity" breast-feeding a child, with three other children playing. There is an imprint of the artist's thumbprint in the clay.
Document 13: A Faun Teased by Children: Bacchanal: A Faun Teased by Children is a marble sculpture by Italian artists Gian Lorenzo Bernini and his father Pietro Bernini. It was executed in 1616 and 1617, when Gian Lorenzo was not yet twenty years old. It is currently in the Metropolitan Museum of Art in New York.
Document 14: Memorial to Ippolito Merenda: The Memorial to Ippolito Merenda is a funerary monument designed by the Italian artist Gian Lorenzo Bernini between 1636 and 1638. Along with the similar monument for Alessandro Valtrini, this artwork was a startling new approach to funerary monuments, incorporating dynamic, flowing inscriptions being dragged by a moving figure of death. It is in the church of San Giacomo alla Lungara in Rome.
Document 15: Elephant and Obelisk: It turned out to be the last commission Pope Alexander VII would ask of Bernini, as he died in May 1667. He was succeeded by Pope Clement IX.
ground_truth: Pietro Bernini
sub_queries: Who developed Elephant and Obelisk? Answer: Gian Lorenzo Bernini
Gian Lorenzo Bernini >> father Answer: Pietro Bernini