"Pope/bishop Hyginus" is a fake, he really matches Hadrian.
Some extra details matches evidences from their biographies:
Hyginus is pretty certainly either/both Hadrian &/or Antoninus Pius? (Hadrian is pretty certainly any/all of either "pope Sixtus", "pope Telesphorus" &/or "pope Hyginus.) (Antoninus Pius is definitely "pope Pius", and he may also possibly be "pope Hyginus"? Though it looks like Hyginus better maches Hadrian.)
-- Hyginus: Name Hyginus/Yginos. -- Hadrian: i. Name Hadrianus. ii. Hadrian's Masoleum later Castel Sant'Angelo. iii. Ignatius in/during Hadrian's reign? iv. Hyacinthus was a beautiful youth loved by Apollo, like Hadrian loved beautiful Antinous. Hyacinth supposed to be from 'ai' "woe", compare Hadrian grieved Antinous' death. v. Hyginus could be related to hygene? In Hadrian's reign "If you and your children are in health, it is well; I and the legions are in health." [fell ill. ailing. suffering poor health c136.]
-- Hyginus: Born in 78 ad. Reigned 136/138/139-140/142, "4 yrs". Died aged "62". [11 Jan. 5 jan. 3 Jul.] -- Hadrian: Born in 76 ad. Reigned 117-138. [Antinous 123/124-130.] "4 yrs after". 4th yr of 227th Olympiad. [3&a1/2 years seige Beitar.] Died aged 62. [24 jan. 10 jul. 10 aug.]
-- Hyginus: Called "Graecvs". "Greek by birth" (born in Athens Greece). -- Hadrian: Nicknamed 'Graeculus' "Greekling". Was a Phil-Hellene/Helleno-phile, "Hadrian's defined Greekness", ardent admirer of Greece, wanted to make Athens capital. He visited/travelled to Greece/Athens. Legio V Macedonica. The 'Adriatic Sea'? [Medusa on chest?]
-- Hyginus: previously a Philosopher. -- Hadrian Attended lectures of philosopher Epictetus. Familiar with the work of the philosophers Epictetus, Heliodorus and Favorinus.
-- Hyginus: Was "Pope/Papa/PP / Bishop / [Prince of Apostles] / [Pontiffex]". Successor of Peter (who had a bushy beard). -- Hadrian: Emperors from Augustus to Theodosius were Pontifex Maximus. Hadrian's mausoleum later converted into a papal fortress. "Prince". Popular cult. ("all Roman emps before Hadrian except for Nero were clean shaven". [Nero matches Peter, eg both had bushy beard.])
-- Hyginus: Tradition holds he was martyr(ed) (but they say ancient authorities say nothing as to his having died a martyr). -- Hadrian: By inversion: Persecution of christians of Trajan & Hadrian (3rd of 10 major persecutions from Nero to Diocletian). [Justin Martyr??] '10 martyrs' (Judaic scholars). Bloody repression of Jewish revolt 132-6 (Roman looses heavy, an entire legion destroyed; 580000 Jews killed.) [1 whole legion disappeared/lost/destroyed in British uprising in 119-121 during his reign?]
-- Hyginus: Bearded in pictures. -- Hadrian: Had a beard, which became a popular fashion. Depictions of him have beard (only one bronze head doesn't). ("all Roman emps before Hadrian except for Nero were clean shaven".)
-- Hyginus: decreed that all churches should be consecrated. -- Hadrian: Constructed temple/temples. Rebuilt the Pantheon.
-- Hyginus: "Saint". shown with a halo/aura. -- Hadrian: deified.