Arta (or Artas in Kharoshthi) was the elder brother of the well known Gandhara ruler Maues or Moga.
Kharahostes’s own coins attest that Kshatrapa Kharaostes was the son of Artas (Arta):
Some of Kharaosta's known coins write Ortas instead of Artas.
Scholars state that Yuvaraja Kharaosta Kamuio of the Lion Capital Inscriptions is the same as Kshatrapa Kharaosta, whose coins have been studied by Dr Rapson and Dr Luders. It is now generally agreed that Kshatrapa Kharaosta was son Arta, and that Yuvaraja Kharaosta and Kshatrapa Kharaosta were one and same historical personage.
The Inscriptions A and E on the Mathura Lion Capital style Kharaosta as Yuvaraya Kharaosta Kamuio.
Based on the estimates of the relative ages of various personages portrayed in Lion Capital Inscriptions, Dr Stein Konow has determined that Yuvaraja Kharaosta Kamuio (i.e. son of Artas) was the father of Aiyasi Kamuia, the chief queen (Agra-Mahisi) of Saka Mahakshatrapa Rajuvula.See also: [1].
An older view was that Arta, the father of Kharaosta, was the first husband of Rajuvula's chief queen who had married Rajuvula after Arta's death. However, Dr S Konow does not accept this view. The fact that last name Kamuia has been used both by Yuvaraja Kharaosta as well as by princess Aiyasi clearly proves that Aiyasi Kamuia was the daughter and not mother of Yuvaraja Kharaosta Kamuio, since it is the father's and not mother's lineage which is adopted by their off-springs.
It appears that Arta (Artas, Ortas) had died before the date of writing of the Mathura Lion Capital inscriptions.
Yuvaraja Kharaosta Kamuio, therefore, was the legitimate inheritor to the position as King of Kings for the kingdom of Gandhara after king Moga.