From slowfood.com: Soda Bread, an article by Darina Allen.
Rotary querns were found in many excavated Iron Age sites (800BC-400AD), which would seem to indicate that bread-making was an integral part of daily life in many Irish homes, made with oats, barley, wheat and rye, which were grown since the early mediaeval period (5-11 Centuries).
For centuries, thin oatcakes were made on a bakestone or griddle over an open fire. Later, breads were leavened with sourdough and barm made from beer, sowans (the fermented juice of oat husks) and fermented potato juice. It was only in the first half of the 19th Century that bicarbonate of soda was introduced, enabling cooks to bake the wide range of soda breads for which Ireland is now so justly famous.
Even in the poorest country cabin, fresh soda bread would have been mixed on a wooden baking board and baked on the griddle, or in the pot oven or bastible, over the embers of the turf fire. [continue]
Related content on Mirabilis.ca:
Ballymaloe Irish bread recipes (Includes links to Darina Allen's soda bread recipes.)