Petra in Aegypto (also spelled Petra in Ægypto) was a Hellenistic city and former bishopric in Roman Egypt and remains a Latin Catholic titular see.
Petra in Aegypto, identified with modern Hagar-En-Nauatiyeh, was important enough in the Roman province of Aegyptus Primus (civil Diocese of Egypt), to become a suffragan of the Patriarchate of Alexandria, but faded, presumably at the advent of Islam.
Little is known not even a single historically documented bishop, as it isn't mentioned in classical reference works like Lequien's Oriens Christianus.
The diocese was nominally restored in 1933 as Latin Titular bishopric of Petra in Ægypto (Latin) / Petra di Egitto (Curiate Italian) / Petren(sis) in Æypto (Latin adjective).
It remains vacant, without a single incumbent. It is of the Episcopal (lowest) rank.