Vintage FDI Cross Crown Daughters of Isabella Filles d'Isabelle Pin Brooch

That's a lovely pin! Based on the imagery of the cross intertwined with a crown and recalling your note about "Daughters of Isabella Filles d'Isabelle Pin," this most likely is a pin associated with the Daughters of Isabella. The cross and crown are significant symbols in Christianity and often represent faith, royalty, and the triumph of the spiritual over the earthly. The Daughters of Isabella is a Catholic women's organization, so these symbols align with their values. It's a beautiful piece! about 2. 1/2 cm