Boreum was a city and diocese in Roman Libya.
It is now a Roman Catholic titular see.
Boreum was important enough in the Roman province of Libya Superior (Libya Pentapolitana; part of Cyrenaica) to become one of the suffragan sees in this province, which depended directly on the Patriarchate of Alexandria (in Egypt) without a proper Metropolitan, but faded like most bishoprics in Roman Africa.
In 1933 the diocese was nominally restored as a Latin titular bishopric of Boreum (Latin) / Borien(sis) (Latin adjective) / Boreo (Curiate Italian).
[4][5] It is vacant, having had only these incumbents, all of the fitting Episcopal (lowest) rank:[6]