Focus on Castor and Pollux (Prado) and explain the Identification.
The lefthand figure was originally headless but was restored in the 17th century, the heyday of interpretive restorations, by Ippolito Buzzi, when the sculpture was in the collection of Cardinal Ludovico Ludovisi, using a Hadrianic-era (ca. 130) bust of Antinous of the Apollo-Antinous type from another statue. The identification of the figures inspired many choices of male pairs during the 17th and 18th centuries. During the 19th century, it became known as "Antinous and Hadrian's genius", to get over the problem of their both being youths, whereas ahistorically it was an important feature of Antinous' relationship with Hadrian that Antinous was a youthful eromenos and Hadrian an elder erastes. Alternatively  "Antinous and a sacrificial daemon" was suggested, in reference to the myth that Antinous had killed himself as a sacrifice to lengthen Hadrian's life), or simply as Antinous and Hadrian pledging their fidelity to one another.
Other alternative identifications in the past have included:
Hypnos and Thanatos, interpreting the sphere as a pomegranate, symbol of death
Corydon and Alexis
Winckelmann's suggestion of Orestes and Pylades offering a sacrifice to the statue of goddess Artemis, which they wanted to seize, or in front of the tomb of murdered Agamemnon. Winckelmann was the first to publish the sculpture, in Monumenti Antichi Inediti 1767, pp xxi–xxii.All these identifications are now thought to be erroneous and simply due to the figure's restoration as Antinous: the group is now accepted as Castor and Pollux, offering a sacrifice to Persephone.  Such an identification is based on the right-hand figure, who holds two torches, one downturned (on a flower-wreathed altar) and one upturned (behind his back), and on identifying the woman's sphere as an egg (like that from which the Dioscuri were born).  The interpretation was supported by Goethe, who owned a cast of the group.Some scholars assert that the statute group was originally created by the ancient sculptor Pasiteles.
Ippolito Buzzi Ludovico Ludovisi Persephone egg Alexis pomegranate Artemis Winckelmann Pylades right Hadrian Antinous Ludovisi Goethe Thanatos eromenos Orestes erastes daemon Hypnos Corydon genius Pasiteles left Castor and Pollux