The historical region of Maishan or Maysan (Syriac: ܡܝܫܢ) is situated in southern Iran.
The last metropolitan of Maishan, the noted East Syriac author Shlemun (Solomon) of Basra, is attested in 1222, and it is not clear when the province ceased to exist.
[8] The bishops Akaï (or Abaï) and Maraï, both styled 'bishop of Prath, metropolitan of Maishan', were among the signatories of the acts of the synod of Babaï in 497.
[9] The bishop Taïmaï, son of Dadishoʿ, of Prath d'Maishan was consecrated metropolitan of Maishan during the patriarchal schism between Narsaï and Elishaʿ in the 520s and 530s.
He was deposed and excommunicated by the patriarch Mar Aba I in 540 'as a bad worker in the church of God, on account of the divisions and dissensions he had stirred up, the oaths he had violated, and the anathema which he had delivered against him'.
He was replaced by the bishop Yohannan, 'metropolitan of Wahman-Ardashir and of all Maishan', who was among the signatories of the acts of the synod of Mar Aba I in 544.
[10] The bishop Shemʿon, 'bishop, metropolitan of Prath d'Maishan', was among the signatories of the acts of the synods of Ezekiel in 576 and Ishoʿyahb I in 585.
[15] The metropolitan Isho'dnah, who wrote the Book of Chastity and a lost three-volume history, probably reigned in the 860s and 870s, but possibly earlier around 850.
[23] He died at an unknown date during the reign of the same patriarch, and was buried in the church of Suq al-Thalatha in Baghdad.
[24] The metropolitan Shlemun of Maishan, a noted East Syriac writer and author of the Book of the Bee (translated into English and edited by E. A. Wallis Budge in 1886), was present at the consecration of the patriarch Sabrishoʿ IV in 1222.
[34] The deacon and secretary Narsaï was among the signatories of the acts of the synod of Acacius in 486, on behalf of the bishop Bagesh of Rima.
[44] The priest and secretary Joseph was among the signatories of the acts of the synod of Acacius in 486, on behalf of the bishop Eliya of Nahargur.
The Nestorian monastery of Mar Yohannan of Dailam in Ubullah, reputedly founded by the legendary apostle Mari, was still functioning as late as the twelfth century.