I think I would find a new project.

I would throw out the old project and buy a brand new one. Floss and fabric are bound to deteriorate after 47 years. Aren't the threads in your old stash rotted by now? You really mix old and new thread??

As painful as it can be, I would call it a day on the pattern. If it's been this long, 47 years, and it is not complete, declutter and give it away to GoodWill or Salvation Army.

I would toss it and find a new project.
Mary

If you've spent hours/days online searching and still haven't found it, maybe it is time to let it go...find something new. As for the age of the floss, I found a piece I worked on 30 gears ago, I washed it/finished it, and used the same floss I bought with the pattern, then washed again, it turned out beautifully. The whole thing was in a large John A Brown bag, the floss was in sealed baggies, labeled, on a ring...the piece was on a loosened scroll frame inside a muslin bag. The magazine was aging, but still pliable, the copies I made slightly yellowed. It helped, I think, that it was linen, but I was impressed that dyes didn't bleed, fade...I'm just freaking lucky, I think. 😉
Tapestries, needlework, centuries old, usually done in silks are still around...some in better shape than others...but still here. Silk will begin to cut other fibers...so much stronger. It cotton has proved pretty sturdy, too. I would swear by DMC, but I suspect fibers and dyes have changed over the years...so luck might have a lot to do with aging, going forward... Now, ain't THAT the truth? 😊

I agree with the others about looking for a newer pattern similar to your ‘old’ one. Everyone understands how frustrating it can be trying to find a pattern that just can’t be found. I have a 1990’s pattern that I’ve been looking for
But I’ve pretty much given up on it and turned my attention to other beautiful patterns. I still hope I may inadvertently run into the pattern in my Internet ‘wanderings’, but I’m no longer actively looking for it.
And without attempting to get too analytical about it, I
Think that maybe I wasn’t meant to find it....

As hard as it is to part with old things, I agree with the other stitchers on here. Find something new that is similar to this piece. The thread will be too old to use. I had a container of thread that my mom gave me from my Great Aunt. I finally parted with it because it was just old and breaking and I couldn't match any of the colors. I still have the tin and fill it with newer, fresh thread.
Happy Stitching,
Jacquie