I always found it interesting that the Irish in Ireland don't eat Corned Beef and Cabbage. Traditionally, in Ireland, the simmered meal is Bacon and Cabbage, Bacon being the term for a variety of pork cuts Cured and Smoked, so most likely Shoulder Bacon, Back Bacon or Ham, Cabbage and Potatoes.
The tradition of Corned Beef and Cabbage is Irish/American. Just before and continuing through the Irish Potato Famine of the 1840's, great numbers of Legally Invited Irish Immigrants made their way to The US. As most 18th and 19th century immigrants did they arrived in NYC. The established Grocery Vendors were predominantly Jewish. Pork not being readily available, the Irish were introduced to Cured Beef packed in Salt. A cheap cut of Beef packed in Corn Kernal sized Rock Salt, was Brisket. This now named CORNED BEEF, became a suitable replacement for Cured Pork in the Cabbage and Potato dish and the rest is American History...JJ