Lovely picture, I had no idea that Marina had used the parure for a formal portrait.
Here is my timeline:
1955: Marina's sister Olga has worn the ruby parure at the pre-wedding reception of Maria Pia di Savoia & and her son Alexander.
1956: Queen Frederica is said to have worn it at a SV to West Germany, but I have no picture of this event.
1957: GD Elena, mother of Olga and Marina, dies
1962: The earliest picture I have for Frederica wearing the parure is the pre-wedding gala of Sophia and Juan Carlos.
Some say that Elena left the tiara to Frederica in her will. But it seems that Frederica has worn it before Elena died. And why on earth would a mother of three leave valuable jewels to a distant relative? I would rather believe that either Elena or her heirs sold it discreetly. And looking at the timeline, it suggests that Elena sold it before her death. But of course, that is just an educated guess.