Isias, surnamed Philostorgos or Philostorgus (Greek: η Ισίας Φιλόστοργος, meaning Isias the loving one) was a Princess of Cappadocia who lived in the 1st century BC. Through her marriage to King Antiochus I Theos of Commagene, she became the Queen of Commagene. Very little is known on her. She was half Persian and half Greek. Isias was the daughter of King Ariobarzanes I of Cappadocia and his wife Queen Athenais Philostorgos I, while her brother was King Ariobarzanes II of Cappadocia.

Isias and Antiochus I had five children who were:

She appeared to have died of unknown causes sometime between the late 30s or early 20s BC. Isias was buried along with her daughter and her granddaughter on a burial site. This burial site was a monument known as the Karakush or Karakus Tumulus, also known as The Black Bird. The monument received its name because there is a column topped by an eagle, which has earned the mound name.

This burial sanctuary was constructed and built by her son King Mithridates II of Commagene. Mithridates II built this sanctuary to bury and honour the lives and the memories of Isias, her daughter Antiochis and her granddaughter Aka I of Commagene. It is located 12 km or 7.5 miles from Kahta, Turkey. Each tumulus is surrounded by groups of three Doric Columns. Each column was about 9 metres or 29.5 feet high. It is topped with steles, reliefs and statues of a bull, lion and eagle.

This monument has Greek honorific inscriptions, which provides information about this site. It is inscribed on the external face of the two drums of the central column of the Northeast. Skipping a couple of phrases where restoration has been doubtful, the inscription reads:

Isias’ name also appears in another honorific inscription dedicated by Mithridates II at the tomb of her other daughter Laodice:

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