Officially called NCE 156, the inscription is written in Greek and is dated to the latter half of the second century, a time when the Roman Empire was at the height of its power. An inscription is an artifact containing writing that is carved on stone. The only other written Christian remains that survive from that time period are fragments of papyri that quote part of the gospels and are written in ink. Stone inscriptions are more durable than papyri and are easier to display. NCE 156 also doesn't quote the gospels directly, instead its inscription alludes to Christian beliefs.
http://www.livescience.com/16319-earliest-christian-inscription-pagan-artifacts.html
http://www.cbsnews.com/stories/2011/09/30/scitech/main20113931.shtml
