Hi, JT, welcome to the forums!
I wouldn't mess with it. It looks like nothing but positive history, and it's a 15-year-old tradeline.
It was probably under a different name back in 1992. Bank One swallowed up a lot of other banks before being swallowed itself by Chase. Here's a link to a Wiki article, with a hilarious list of begats:
http://en.wikipedia.org/wiki/Bank_One
Maybe you'll recognize a ghost bank on the list as one that you once had.
If it really freaks you out, you can close it after the mortgage is all wrapped up, but please read first about closing credit cards. As long as there doesn't seem to be any fraud involved, there's no real reason to mess with it. This looks like one of the rare instances when a consumer gets lucky.
* Credit is a wonderful servant, but a terrible master. * Who's the boss --you or your credit?
FICO's: EQ 781 - TU 793 - EX 779 (from PSECU) - Done credit hunting; having fun with credit gardening. - EQ 590 on 5/14/2007