Probably about the time writing first appeared. Since ancient times, poetry has been written down, to share with as many people as possible and benefit future generations. The ones that weren't written have been lost to us forever. That poetry should be spoken, rather than read, is a matter of opinion.

Poetry cannot be contained in categories... It is both an oral and written art. It is music and meter. It is proper and vulgar, quaint and violent. It is iambic pentameter, and it is the roughest prose. Poetry is the expression of the human soul in words. You cannot box that in.

In America, poetry was still experienced primarily as an oral art form through the beginning of the twentieth century. Its atrophy into an almost exclusively written art can be connected to the rise of free verse during that time. Meter and rhyme are the most significant and pleasurable auditory qualities of poetry, so their removal naturally diminished the art's oral experience. However, the post-modernist revolution also rebelled against the traditional method of teaching poetry--by memorization and recitation. Most people were already encountering poetry as readers rather than listeners, but that presentation had at least been forcing them to also experience it as spoken words. Recommended reading: "Committed to Memory" by John Hollander

1) I don't think that poetry ever stopped being an oral art! In the last few centuries, a kind of visual poetry using some typographic elements has appeared. But most of poetry is mainly oral I think. You just cannot appreciate in its fullness if you do not hear or read it aloud yourself. It can also be interesting to learn it by heart. 2) Today, we have also "sound poetry": "Sound poetry is a form of literary or musical composition in which the phonetic aspects of human speech are foregrounded at the expense of more conventional semantic and syntactic values; "verse without words". By definition, sound poetry is intended primarily for performance." Source and further information: http://en.wikipedia.org/wiki/Sound_poetry 3) In a restricted sense, poetry was an oral art before, as still is today "oral poetry": "Oral poetry is a form of poetry that is transmitted orally and memorized or improvised rather than written down. It exists primarily within oral cultures, though some forms of it can survive after a culture has made the transition to literacy. Oral poetry differs from oral literature in general, which can include shorter and more variable pieces and can coexist much more with written literature, by certain consistencies within its form, which were brought to the attention of scholars by Albert B. Lord. Foremost among these consistencies is the use of formulaic language: repeated phrases that help poets and singers structure and remember their poems." Source and further information: http://en.wikipedia.org/wiki/Oral_poetry In this restricted sense, most of today's poetry exists in a written form and not just in an oral form. However, the transition to written poetry has happened progressively and very slowly after the invention of the written word.