It was rebuilt by Empress Helena, mother of Emperor Constantine who commissioned the Church of the Nativity in 327. It was rebuilt after warfare in 529 and is in very much the same condition as it was since then. The Grotto in the Church is associated with cave where Jesus was born.
The Grotto can be accessed by descending the stair into a very tight narrow altar where many pilgrims visit to pray. The entrance to the Church is currently placed sideways with respect to the altar. The Church has been altered and adorned by many Christians over history and is a revered place throughout Christendom.