Hagios Ioannes Prodromos en tois Stoudiou (Saint John the Forerunner at Stoudios), often shortened to Stoudios or Stoudion (Latin: Studium), was historically the most important monastery of Constantinople (modern-day Istanbul), the capital of the Eastern Roman Empire. The residents of the monastery were referred to as Stoudites (or Studites). Although the monastery has been derelict for half a millennium, the laws and customs of the Stoudion were taken as models by the monks of Mount Athos and of many other monasteries of the Orthodox world; even today they have influence.
The ruins of the monastery are situated not far from the Propontis (Marmara Sea) in the section of the city called Psamathia, todays Koça Mustafa Paşa. It was founded in 462 by the consul Stoudios (Latin: Studius), a Roman patrician who had settled in Constantinople, and was consecrated to Saint John the Baptist. Its first monks came from the monastery of Acoemetae.
Hegumenos (abbot) Sabbas zealously defended the Orthodox doctrines against the Iconoclasts at the Seventh Ecumenical Council in Nicaea (787). His successor was Theodore the Studite to whom the monastery owes most of its fame, and who especially fostered academic and spiritual study. During St. Theodore's administration also the monks were harassed and driven away several times, some of them being put to death.
Theodore's pupil Naukratios re-established discipline after the Iconoclastic dispute had come to an end. Hegumenos Nicholas (848-845 and 855-858) refused to recognize the Patriarch St. Photios and was on this account imprisoned in his own monastery. He was succeeded by five abbots who recognized the patriarch. The brilliant period of the Stoudios came to an end at this time.
In the middle of the eleventh century, during the administration of Abbot Simeon, a monk named Niketas Stethatos (also known as Nicetas Pectoratus), a disciple of Symeon the New Theologian, made a virulent attack on the Latins in a book which he wrote on the use of unleavened bread, the Sabbath, and the marriage of priests. In 1054 he was obliged to recant in the presence of the emperor and of the papal legates and to throw his book into the fire, but he renewed his dispute later.
As regards the intellectual life of the monastery in other directions it is especially celebrated for its famous school of calligraphy which was established by Theodore. The art of manuscript illumination was cultivated, with many brilliant products of the monastic scriptorium now residing in Venice, Vatican City, and Moscow (e.g., Chludov Psalter).
In the eighth and eleventh centuries the monastery was the centre of Byzantine religious poetry; a number of the hymns are still used in the Orthodox Church. Besides Theodore and Niketas, a number of other theological writers are known. Three of the Stoudite monks rose to become the ecumenical patriarchs; and three emperors - Michael V, Michael VII, and Isaac I Komnenos - took monastic vows in the Stoudion shortly before the end of their lives.
In 1204, the monastery was destroyed by the Crusaders and was not fully restored until 1290. The Russian pilgrims Anthony (c. 1200) and Stephen (c. 1350) were amazed by the size of the monastic grounds. It is thought that the cloister sheltered as much as 700 monks at the time. The greater part of the monastery was again destroyed when the Turks captured Constantinople in 1453.
Following the earthquake, a group of Russian Byzantinist scholars, led by Fyodor Uspensky, opened the Russian Archaeological Institute on the monastery grounds, but its activity was suppressed in the wake of the Russian Revolution of 1917. During the subsequent decades, the ruins of the monastery complex were looted by local inhabitants to repair their houses, while the magnificent 13th century pavement still lies open to elements "and disappears slowly but steadily".