After doing a little research, I found that what I have bought in bakeries in years prior that was advertised as "Irish Soda Bread" is not even close to the daily quick bread baked in Ireland mid-1800's through the turn of the century. Most of the Irish Soda Bread I've had commercially prepared was a yeasted bread with raisins. According to the "Society for the Preservation of Irish Soda Bread" that is not even close and it makes sense. Soda Bread was a daily meal bread, so it wouldn't be sweet or difficult to make. Like American southern biscuits (and the recipes closely resembles that) it would be something homemakers would make quickly and easily every few days to be eaten during regular meals. So the basic REAL soda bread contains just four ingredients: flour, salt, baking soda, and buttermilk. Another little tidbit of interest is that not only does this bread not contain yeast, it didn't even come into existence until the commercial availability of "bicarbonate of soda" or baking soda in the mid-1800's.
Click on either of the links provided here to the Irish Soda Bread web site for more information. I found the author to be very informative and passionate about her subject, to the point of being on the entertainingly cranky side about what does NOT constitute traditional Irish soda bread. It's a fun read.