Posted to the Main List by C. Equitius Cato
"Fertur autem in carminibus Marcii vatis, cuius duo volumina inlata sunt in senatum, inventum esse ita scriptum: Hostem, Romani, si ex agro expellere vultis, vomicam quae gentium venit longe, Apollini censeo vovendos ludos qui quotannis comiter Apollini fiant. His ludis faciendis praesit is praetor qui ius populo plebique dabit summum: decemviri Graeco ritu hostiis sacra faciant. Hoc si recte facietis, gaudebitis semper fietque res publica melior: nam is divus extinguet perduelles vestros qui vestros campos pascunt placide. Ex hoc carmine cum procurandi gratia dies unus rebus divinis impensus esset, postea senatus consultum factum: uti decemviri, quo magis instruerentur de ludis Apollini agundis reque divina recte facienda, libros Sibyllinos adirent. In quibus cum eadem reperta nuntiatum esset, censuerunt Patres: Apollini ludos vovendos faciendosque, inque eam rem duodecim milia aeris praetori et duas hostias maiores dari, decemvirisque praeceptum: ut Graeco ritu hisce hostiis sacrum facerent, Apollini bove aurato et capris duabus albis auratis, Latonae bove femina aurata. Ludos in circo populus coronatus spectare iussus. Haec praecipue traditur origo ludorum Apollinarium." - Macrobius, Saturnalia XVII.28-30
During a rather bad year (212 BCE) in the Second Punic War (though they did have a good win at Syracuse) and several years after their crushing defeat by the Carthaginian Hannibal at the Battle of Cannae, the Romans consulted the ancient seer Marcius for his reading from the sacred texts, the Sibylline Oracles. Marcius advised them to hold games in honour of the Greek sun god, Apollon, in order to obtain his aid. Four years later when a plague broke out, the senators of Rome decided to make the Ludi Apollinares permanent and over the course of the next two centuries the games came to be a festival lasting eight days, the principal sacrifice being made on July 13.
It was stated by some of the ancient annalists that these ludi were instituted for the purpose of obtaining from Apollo the protection of human life during the hottest season of summer; but Livy and Macrobius adopt the account founded upon the most authentic document, the carmina Marciana themselves, that the Apollinarian games were instituted partly to obtain the aid of Apollo in expelling the Carthaginians from Italy, and partly to preserve, through the favour of the god, the republic from all dangers. The oracle suggested that the games should be held every year under the superintendence of the praetor urbanus, and that ten men should perform the sacrifices according to Greek rites. The senate complying with the advice of the oracle made two senatusconsulta; one that, at the end of the games, the praetor should receive 12,000 ases to be expended on the solemnities and sacrifices, and another that the ten men should sacrifice to Apollo, according to Greek rites, a bull with gilt horns and two white goats also with gilt horns, and to Latona a heifer with gilt horns. The games themselves were held in the Circus Maximus, the spectators were adorned with chaplets, and each citizen gave a contribution towards defraying the expenses. The Roman matrons performed supplications, the people took their meals in the propatulum with open doors, and the whole day — for the festival lasted only one day — was filled up with ceremonies and various other rites. At this first celebration of the ludi Apollinares no decree was made respecting the annual repetition suggested by the oracle, so that in the first year they were simply ludi votivi or indictivi. The year after (211 BCE) the senate, on the proposal of the praetor Calpurnius, decreed that they should be repeated, and that in future they should be vowed afresh every year. The day on which they were held varied every year according to circumstances. A few years later, however (208 BC), when Rome and its vicinity were visited by a plague, the praetor urbanus, P. Licinius Varus, brought a bill before the people to ordain that the Apollinarian games should in future always be vowed and held on a certain day (dies status), on prid. Non. Quin. ‡, which day henceforward remained a dies sollemnis. The games thus became votivi et stativi, and continued to be conducted by the praetor urbanus.
Livy, Macrobius, Smith's Dictionary, Wikipedia