I know it is just me but I am surprised people don't know the history of Target. This is all from recollection:
Dayton's (predecessor to Target) started in early 20th century. In about a few years Dayton's merged with Hudson's and became the Dayton-Hudson company for the rest of the century. In 1962 it started Target as an discount alternative. Along the way, it acquired some other chains -- such as Mervyn's in the 70s and Marshall Fields. In 2000, Dayton's, seeing the popularity of the Target brand, renamed itself Target, converting the Dayton-Hudson's stores to Marshall Fields and eventually selling off Marshall Fields and Mervyns.