In a thread....someplace, maybe on Cubits.....Polly explained the "Caesar's Brother" thing several years ago. Several being sold , or passed around, under that name, and apparently none of them the "real deal". It is an older form, (and probably "self seeded" ....that's how the "real deal" was lost), and quite hardy. Not a fancy flower, but, it makes a good "statement".
I don't have a picture....but, when it blooms, I'll post one.....but Polly sent me an iris that she said "wasn't CB, but, it's as close as you will ever come". I spent a while 'searching 'for that thread....and can't find it.