Jesuit ring" Even though the design looks like it says IXXI, it's actually an interlocked A and M, standing for Auspice Maria - under the protection of Mary.
1600's Jesuit IXXI ring? Yes... - Treasure Hunting Forum
Complete ixxxi ring goud met diamant - Beadle
Tiffany & Co. 18k White Gold Diamond 0.12 CTW Atlas Ring Band Size 6.5 | eBay