Did you ever know the name of the iris, (in other words if you heard the name would it ring a bell?) do you have any old order receipts that would show it? Sometimes if it wasn't too long back a seller will keep a record of what was sold to whom.
where did you obtain it, how much did you pay for it, and how long have you had it? Does it have purple based foliage? What does it smell like ect.