Thanks all for the suggestions, they've all gone down on my list to buy gradually.

I know that there are great oral traditions within Irish, did works of literature only really come about during the Gaelic revival to present? Or are there any great works before that? (aside from histories & religious texts)

I'm not quite sure what you mean. There are these kinds of texts that you can find here for example -
www.luminarium.org/mythology/ireland
www.maryjones.us/ctexts/index_irish.html -
but it would be too long to list all the relevant websites here. There's the National Museum in Dublin where you can look at historical manuscripts in Irish and you can buy a nice booklet on-line from the RIA called 'Aon amharc ar Éirinn' (ISBN 978 1 908996 22 0) which gives you an accurate idea of what authentic Irish manuscripts look like and what they wrote about.

Here's another well-known poem in Old Irish that you might not have heard of -
Pangur Bán
Again it has already been mentioned here on the forum, but here's a copy of the original version followed by a translation into modern Irish, followed by a list of vocabulary. You might like to do as I did - I printed it out and pasted the two versions side by side, so it was easier to understand.
If you want to see what the original looks like, it's on Wikipedia or you can go directly to the website of the monastery in Austria where it's still there in their library. Irish monks and priests, as well as their writings, were to be found in many places across Europe in the Middle Ages and of course even more during the Penal Times. Here in Paris at the former Irish College in the Latin Quarter, they even managed to get a French printer to assist in creating one of the first Irish-English dictionaries, basing the print on handwritten lettering.

www.ibiblio.org/gaelic/Rhodes/sb.12.html

I don't think I knew what I meant ether in English literature you have fiction going back a long time, I was just wondering if the Irish language had the same depth pre-Gaelic revival with it being a largely oral culture. I might not know what I am talking about though

Thanks for the poem, thats an invaluable resource, déanfaidh mé staidéar é sin an deireadh seachtaine.

There is a huge amount of poetry and historical texts, as well as a good amount of mathematics and linguistic work.

Prose fiction was relatively uncommon. It would be mostly the historical sagas, which are pseudo-history anyway.

_________________
The dialect I use is Cork Irish.
Ar sgáth a chéile a mhairid na daoine, lag agus láidir, uasal is íseal

The Irish literary tradition goes back farther even than in English. But you really have to consider the accessibility to even the average native speaker. A native speaker of Irish is not going to be able to pick up a text from the 8th or 9th century and read it any better than one would be able to just pick up a copy of Beowulf in the original language and read it. An untrained native English speaker would also find it impossible to pick up Chaucer in the original language as well and that's the 14th century nor even Shakespeare from the 16th.

So while there is a massive amount of literature going back that far due to historic events in the 18th century like bliain an áir the destruction of the Gaelic nobility and subsequent collapse of the poetic class 17th/early 18th century the literary tradition in Ireland stumbled from a massive one-two punch only to be dealt a knockout blow in the 19th century by an Gorta Mór. And it's after that when the Gaelic revival begins. It's not to say there was nothing being produced back then but you can't really compare it to the same period in the English speaking world where Louisa May Alcott, Dickens, et al. were active and in print. Anything from that period in Irish would have been in manuscript and poorly distributed. After all most of the people who spoke Irish at this time could not read and those who were more well off were leaving the country. But here are some works I am aware of:

An Haicléara Mánas. A nineteenth-century text from Clifden, Co. Galway, edited by Nancy Stenson
Cath Muighe Tuireadh. The Second Battle of Magh Tuireadh edited by Brian Ó Cuív

This is not literature but as a learner I really like graded readers! Fionn Mac Cumhaill – Bosca 4 leabhar agus CD atá ann agus tá Tadhg Mac Dhonnagáin, an t-údar, ag léamh na labhar os ard.