Claim: The Bible is referred to as 'the greatest story ever told' because it is based on an ancient and old story that predates Christianity.
Verdict: Correct (60% confidence)
Explanation: According to the University of Missouri-Kansas City, the Bible is often called 'the greatest story ever told' (law2.umkc.edu). Additionally, HubPages confirms that the Bible's stories have origins that predate Christianity, as the Bible was written hundreds of years after Christ (hubpages.com). These sources support both components of the claim: the attribution of the phrase to the Bible and the historical origins of its stories predating Christianity.