The year was marked by a grave sickness that hushed everyday life. The duumvirs undertook numerous rites as instructed by sacred texts to mollify the gods and eradicate the plague affecting the population. Nevertheless, the death toll was substantial, impacting both the urban centers and rural areas, claiming the lives of both humans and animals. The substantial decline in agricultural labor raised concerns about a potential famine as a consequence of the widespread disease.

In 433 BC, in response to a plague, a vow was made to Apollo Medicus, the deity of healing, which led to the construction of a temple two years later, attributed to Julius Caesar’s forebear (Livy, IV.29). This temple stood as the sole temple dedicated to Apollo in Rome until Augustus erected another on the Palatine hill. The Ludi Apollinares, festivities held in honor of Apollo, were first established in 212 BC and took place every July. The temple itself underwent several restorations, the last one executed by Gaius Sosius, who was among Caesar’s close allies and held the consulship in 32 BC. Despite being recorded as a supporter of Caesar, Sosius had opposed Octavian and allied with Antony at Actium in 31 BC. The temple’s intricately decorated cella might suggest that Augustus completed its construction and later changed the dedication date to correspond with his birthday on September 23, as he was also in the process of establishing his own temple to Apollo, dedicated in 28 BC. Notably, the frieze showcases a battle against northern tribes, a reference to Augustus’s celebrated victories over Germanic nations in 29 BC.

The temple’s excavation, conducted between 1926 and 1928, uncovered Corinthian columns from the right side of the temple’s entryway, currently elevated on a base of modern travertine and tufa. These columns are intricately designed, featuring alternating wide and narrow flutes.

Originally, the temple façade comprised six columns made of Luna marble across the front and two on each side, alongside seven engaged travertine columns along the cella’s wall. Adorning the capitals are laurel sprigs, sacred to Apollo, situated beneath the elaborate volutes. The entabulature is embellished with laurel branches linking candelabras with tripod bases and bucrania (ox skulls).

Internally, the cella displays opulent decorations crafted from colored marbles and features a Corinthian colonnade, with an upper frieze illustrating scenes of combat and triumphal parades. Aediculae, or niches for statues, were interspersed between the columns. Pliny (XIII. 53, XXXVI.28, 34; XXXV.99) noted that the temple was home to an array of artworks centered around Apollo, most likely imported to Rome by Sosius. Among these, the renowned sculptures of Niobid’s children, attributed to either Scopas or Praxiteles, were highlighted, although there remained uncertainty even in ancient times regarding their true origins.