I thought I had it. So I tried to check my eBay history. But that only goes back two calendar years prior to the current one - that would be 2016, now that it's 2018. And eBay's feedback system only shows item numbers, not titles, now. Which I guess is good for privacy, but sucks for researeching.
What about PayPal? Their history is only about as long as eBay's, which means there would be no details on my 2014 purchases.
Now, you may be wondering why I wouldn't just go home and check my collection to see if I have the set. I would have done that, but it's in America, and I'm in Japan.
I haven't been the best blogger in the world, but I have posted a lot about my goals and collection progress. So I pulled up Blogger, and searched my posts for Gypsy Queen. And lo and behold, in mid-2014, I posted an update on my yearly goals. And in that post, I mentioned I had the master set of Gypsy Queen.
It's a good thing I blog!