One is mine, one is @Aethelred's, and one is his now but formerly mine. The Antoninus Pius is in my present collection. The Hadrian also used to be mine. (Prior provenance to the Boston Museum of Fine arts and @AncientJoe.) It has since gone on to live with @Aethelred, and I have lamented that more than once, but I do get visitation rights once a year when I get up to North Carolina. Boy, that stern portrait is stunning, ain't it? The Marcus Aurelius belongs to @Aethelred and has resided in his collection for decades, I believe. He wanted to acquire my Antoninus Pius on this recent visit, and I'll admit it looks nice with the other two, but I managed to resist, for once. It's enough that he wrested that Hadrian from my grasp already, right?