Abraham of Bulgaria was a Christian

Christian

A Christian is a person who adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus of Nazareth as recorded in the Canonical gospels and the letters of the New Testament...

 convert from Islam

Islam

Islam . The most common are and .   : Arabic pronunciation varies regionally. The first vowel ranges from ~~. The second vowel ranges from ~~~...

 later made a martyr

Martyr

A martyr is somebody who suffers persecution and death for refusing to renounce, or accept, a belief or cause, usually religious.-Meaning:...

 and saint

Saint

A saint is a holy person. In various religions, saints are people who are believed to have exceptional holiness.In Christian usage, "saint" refers to any believer who is "in Christ", and in whom Christ dwells, whether in heaven or in earth...

 of the Russian Orthodox Church

Russian Orthodox Church

The Russian Orthodox Church or, alternatively, the Moscow Patriarchate The ROC is often said to be the largest of the Eastern Orthodox churches in the world; including all the autocephalous churches under its umbrella, its adherents number over 150 million worldwide—about half of the 300 million...

.

He was born in Volga Bulgaria

Volga Bulgaria

Volga Bulgaria, or Volga–Kama Bolghar, is a historic Bulgar state that existed between the seventh and thirteenth centuries around the confluence of the Volga and Kama rivers in what is now Russia.-Origin:...

, amongst the Muslim

Muslim

A Muslim, also spelled Moslem, is an adherent of Islam, a monotheistic, Abrahamic religion based on the Quran, which Muslims consider the verbatim word of God as revealed to prophet Muhammad. "Muslim" is the Arabic term for "submitter" .Muslims believe that God is one and incomparable...

 Volga Bulgars in what is now Tatarstan

Tatarstan

The Republic of Tatarstan is a federal subject of Russia located in the Volga Federal District. Its capital is the city of Kazan, which is one of Russia's largest and most prosperous cities. The republic borders with Kirov, Ulyanovsk, Samara, and Orenburg Oblasts, and with the Mari El, Udmurt,...

, Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

. He grew to become a Islam

Islam

Islam . The most common are and .   : Arabic pronunciation varies regionally. The first vowel ranges from ~~. The second vowel ranges from ~~~...

ic merchant, and was later converted to Christianity

Christianity

Christianity is a monotheistic religion based on the life and teachings of Jesus as presented in canonical gospels and other New Testament writings...

. He was killed by his compatriots for his conversion circa 1229. His relics are venerated at Vladimir

Vladimir

Vladimir is a city and the administrative center of Vladimir Oblast, Russia, located on the Klyazma River, to the east of Moscow along the M7 motorway. Population:...

 on the Klyazma

Klyazma River

The Klyazma River is a river in the Moscow, Nizhny Novgorod, Ivanovo and Vladimir Oblasts in Russia, a left tributary of the Oka River. The length of the river is 686 kilometres. The area of its drainage basin is 42,500 km². The Klyazma River freezes up in November and stays under the ice...

. His feast day is celebrated on March 6, and the translation of relics is also commemorated on April 1.