(2) _Epodon liber_, B.C. 30, as above. _Epod._ 9 was written shortly after the battle of Actium, 2nd September, B.C. 31, before it was known whither Antony had fled. (3) _Carmina_ (Odes) Books i.-iii., published B.C. 23. In _Od._ i. 12, 45, 'Crescit occulto velut arbor aevo fama Marcellis,' we have a reference to the marriage in B.C. 25 of Augustus' daughter, Julia, to his nephew, Marcellus. Marcellus died in the autumn of B.C. 23, and the lines must have been written before his death. _Od._ ii. 10 and iii. 19 contain references to Licinius Murena, brother of Terentia, Maecenas' wife. Murena was executed for his share in the conspiracy of Fannius Caepio in the end of B.C. 23, and it is improbable that Horace could have made these references after that event.[56] (4) _Epistles_, Book i., published B.C. 20. The date is fixed by _Ep._ i. 20, 26-8, already quoted, p. 164. The year referred to is B.C. 21, and the book was therefore composed in B.C. 20, before December of that year. (5) _Carmen Saeculare_, composed for the _Ludi Saeculares_ of B.C. 17 (see Sueton. quoted above). An inscription commemorating these games was discovered in 1890 on the left bank of the Tiber, and in it Horace is mentioned: 'Sacrificioque perfecto pueri xxvi. quibus denuntiatum erat patrimi et matrimi et puellae totidem carmen cecinerunt eodemque modo in Capitolio. Carmen composuit Q. Horatius Flaccus.'[57] (6) _Odes_, Book iv., published B.C. 13. _Od._ 4 and 14 celebrate the campaign of Drusus and Tiberius in Rhaetia and Vindelicia B.C. 15. _Od._ 2 and 5 were written just before Augustus' return, B.C. 13, from Gaul, where he had been since B.C. 16. (7) _Epistles_, Book ii. _Ep._ ii. 1, to Augustus, was written B.C. 14 in response (see the quotation from Suetonius above) to the emperor's request for a poem addressed to himself, after seeing that no mention was made of him in _Ep._ ii. 2 and the _Epistula ad Pisones_. These are the _sermones quidam_ (both, like _Ep._ ii. 1, on literary criticism) referred to by Suetonius, and not Book i. of the Epistles, where Augustus is frequently mentioned. The date is fixed by l. 15, 'praesenti tibi maturos largimur honores,' etc., referring to the worship of the _numen Augusti_, which was legalized B.C. 14, and by the reference in ll. 252 _sqq._ to the victories of Drusus and Tiberius, and their celebration in _Od._ iv. 4; iv. 14. _Ep._ ii. 2 (to Iulius Florus) was written B.C. 18. Horace hints (l. 25, ll. 84-6) that he has not yet returned to lyric poetry; the epistle was therefore written before B.C. 17. The _Epistula ad Pisones_ or _De Arte Poetica_ was probably written B.C. 17 or 16 after the _Carmen Saeculare_, but before Horace had entered on the composition of the fourth Book of the Odes.