... and "Oy" goes Erin

 Corned Beef and Cabbage is basically an American tradition on St. Patrick's Day started by irish-Americans in the mid 1800's

Some Irish people feel that corned beef and cabbage is about as Irish as spaghetti and meatballs.

Since cows were used for milk rather than meat in poor times in Ireland, beef was a delicacy that was fed to kings. It was more common to celebrate a holiday meal with what they call a ham (Gammon) or bacon joint. ( a cured but unsmoked piece of pork) with their cabbage and potatoes.

 

When many Irish Immigrants came over in the mid 1800's they couldn't find a bacon joint like they had in Ireland, so they found that Jewish corned beef was very similar in texture, and they used that for their holiday celebrations.

 

 http://www.kitchenproject.com/history/CornedBeef.htm