Plancia Magna (Greek: Πλανκία Μαγνά) was a prominent woman from Anatolia who lived between the 1st century and 2nd century in the Roman Empire.
Plancia Magna came from a distinguished family. She was born and raised in Perga, the capital of the Roman province of Pamphylia. Her cognomen Magna, is either from her maternal or paternal grandmother. She was the daughter of Roman Senator, Proconsul Marcus Plancius Varus and the Herodian Princess Julia. Her mother became a priestess and served in the temple of the Ancient Greek Goddess Artemis in Perga. Artemis was the most important Goddess in Perga. Magna’s brother was Roman Senator, Consul Gaius Plancius Varus.
Her maternal grandparents were King Tigranes VI of Armenia and his wife Opgalli, while her maternal uncle was prince Gaius Julius Alexander. Magna’s maternal ancestors were King Archelaus of Cappadocia, King of Judea Herod the Great and his wife Mariamne. Magna along with her brother and maternal cousins were among the last known descendants of the Herodian Dynasty. She appeared to be an apostate to Judaism. It is unlikely that she attempted to exert influence on Judean Politics.
Magna married a man of Roman Senatorial rank called Gaius Julius Cornutus Tertullus, who was the son of a Proconsul and Suffect Consul. Her husband was a local citizen of Perga and his family originated from Pamphylia. Magna bore Tertullus a son and only child, Gaius Julius Plancius Varus Cornutus.