(Approximate) Chronology of Horace's Works

Satires ("Sermones"), Book 1: 35-34 BC

Satires, Book 2: 30-29 BC

Epodes: 30-29 BC

Odes, Books 1-3: 23 BC

Epistles, Book 1: 20-19 BC

Odes, Book 4: 13 BC

Epistles, Book 2: 13 BC

but the Ars Poetica, "Art of Poetry" (Epistle 2.3): between 23 and 17