Many people think it began in medieval market, where people would buy a pig, bring home and slaughter it for food. That makes sense, of course, though the origin of the phrase is rather different.
According to the 12th century records, there was a country in Ireland in which an unusual number of couples were having marital squabbles. Thus, the local elders came up with a proposition: Whichever couple did not quarrel for one year would be awarded a side of bacon.
The custom continued for many years to come, and those who saw a neighbor " bringing home the bacon" knew that all was going well at home.
Much later, the expression came to mean that one was successful in business as well as in domestic affairs, and a man or woman who was able to bring home the bacon was viewed as content in every way.