The Panagia of Blachernitissa (Gr. Παναγία η Βλαχερνίτισσα), also called Blachernae, is a 7th century Byzantium icon from Constantinople preserved in the imperial palace of Blachernai. The icon according to tradition was not written rather it was made from a composition of ashes of 6th century martyred Christians and wax. . It is currently located in Russia at the Tretyakov Gallery.
The Shrine of Blachernai
Blachernai, near the northern tip of the walls of Theodosios, was the site of major shrine of the Virgin Mary in Constantinople built by the Empress Pulcheria (ca. 450). A circular chapel (the Soros), was built by Emperor Leo I (457-474) next to the Church to hold the robe of the Virgin Mary, brought from Palestine in 473. The church was burnt down in 1070. It was rebuilt by 1077 by either Romanos IV Diogenes (1067-71) or Michael VII (1071-87) and then destroyed again 1434. Next to it was a bathhouse where a spring flowed, which still flows in the modern church on the site 
From the time of the Patriarch Timotheos [511-18] there was a procession - the "panhgur j" - which took place each Friday from Blachernai to the Church of the Chalkoprateia, near Hagia Sophia, at the other end of the city :.
The Circular Chapel ("Soros")
The chapel of the Virgin's robe was covered in silver and considered a "reliquary of architectural dimensions". Lay people were not allowed inside but could pray in the main church. . There was a specific icon, the Panagia Hagiosoritissa, associated with this shrine. 
- Wikipedia: Blachernitissa
- Oxford Dictionary of Byzantium (ODB) 1:293; Janin, Eglises CP, 161-71 and the end map entitled "Byzance Constantinople", ref. D2; George P. Majeska, Russian Travelers to Constantinople in the Fourteenth and Fifteenth Centuries, (Washington, D.C.: 1984), 333-337
- Janin, Eglises CP, 177
- ODB 3:1929
- ODB 3:2171
- [Paul Halsall - Response on Blachernae enquiry]
- [Blachernae Icon of the Mother of God "Hodegetria"]
- [Article on The Veil] at the Church of the Panagia Blachernitissa.