looks like Festiva Maxima

The center is similar to festiva maxima, but fm doesn't have a row pink guard petals and this one is smaller than fm.

Another possibility maybe Madame de Verneille. Yours looks very similar to the picture on Adelman's website.

Madame de Verneille is supposed to have a distinct rose scent, does yours, Graycrana4u?

It has a very pleasant scent indeed. But I don't see the single row of guard petals. Look at Rhapsody on page 8 of Adelman's herbaceous plants and see what you think.

It is hard to know. You will probably be the best judge because you get to observe your plant in person and the changes in coloring of the flower as it blooms. Based on your photo, I do not see any pink in the guard petals. All appear to be white. The fact that you acquire this from an older home leads me to believe that it is more likely a classic oldie like FM or MV rather than a recent intro.

Looks just like the ones in my garden that a gardening friend told me were Festiva Maxima. I've always been unsure of it though. It may not show up too much in the photo there, but if like mine, there is just a faint blush pink to the guard petals. Not a huge flower, just doesn't look quite like photos of FM to me & I haven't seen FM in person to compare. Mine weren't purchased but given to me from an elderly relative who had them for years.