It was built in Byzantine times in relation to the "Cave of Apocalypsis" where the apostle St John was in exile from the Romans during the first century.

St John is believed to be one of the 12 original apostles and the creator of the Book of Revelation (The Apocalypse) which he is believed to have written in the cave (which today is a museum).

In the monastery (which is an Unesco World Heritage) is also the skull of another of the 12 original apostles-the skull of St Thomas.

St Thomas is famous for being the one of the 12 apostles who was in doubt of the resurrection of Jesus and got the nickname "Doubting Thomas". According to Christian mythology St Thomas was later confronted with his master and when touching his wounds in palms and feet was convinced of Jesus divinity.

He was later sent east to evangelize christianity and ultimately reached India carrying the faith to the Malabar coast which still today boasts a large native population calling themselves "Christians of St Thomas".

He was speared to death at a place called Calamine on the Malabar coast.

Some christian relics have been found to be fake and the same relic of an apostle or a saint can exist in different places who all claim to be true.

In the case of St Thomas skull there´s some hard evidence that this is really the skull of "Doubting Thomas".

Photography in the cave and inside the monastery is difficult since it´s forbidden.