Metal detectorist Derek McLennan uncovered the 10th-century hoard, which includes silver bracelets and brooches, a gold ring, an enamelled Christian cross and a bird-shaped gold pin, in a Dumfries and Galloway field in 2014.
National Museums Scotland raised £1.98 million to acquire the treasure trove of items for the nation.
Rules on discoveries in Scotland mean only the finder receives payment, differing from the rest of the UK, where awards are split with the land owner.
But it was reported at the time the church would share in the proceeds.
Church trustees are now taking legal action at the Court of Session in Edinburgh.
A Church of Scotland spokesman said: "It can be confirmed the general trustees of the Church of Scotland have raised an action against Derek McLennan.
"As that is now a matter before the court it would be inappropriate for us to provide any further commentary at this time."
Mr McLennan has been contacted for comment.
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