NDXOXCHWDRGHDXORVI

Can you decipher these letters?
A medieval sword that carries a mysterious inscription has baffled historians for centuries. Little is known about [the] double-edged weapon, least of all the meaning behind a cryptic 18-letter message running down the central groove which reads: NDXOXCHWDRGHDXORVI.
Now The British Library have appealed for the public’s help in cracking the conundrum...

The weapon was found at the bottom of the River Witham in Lincolnshire in 1825, but it’s believed the 13th century sword originally belonged to a medieval knight...

The indecipherable inscription is inlaid with gold wire and experts have speculated the letters are a religious invocation since the language is unknown...

Anne Robertson reckons the letters may be the first from each line of a poem – something that’s been seen on other medieval artefacts. A number of people have picked out certain letters which had particular meanings in Latin at the time, such as ND standing for ‘nostrum dominus’ meaning our Lord, and ‘X’ for Christ. Harrison thinks this is the most probable idea so far 'but then it gets more complicated'. 'It's been suggested in the past that it's a relgious inscription and the sword may have been dropped in the river on purpose [for religious reasons] which was not uncommon...'
More details, pix and a video at the link.  I should probably carve TYWKIWDBI on something...