Duchess of Angoulême's Sapphire Tiara

Creation:  This tiara was made by Bapst in 1819.  It was heavily altered using sapphires from the parure's necklace sometime between May 1937 and June 1953.

Materials: sapphires and diamonds

Marchioness of Cholmondeley

Marchioness of Cholmondeley

Provenance:

1. Princess Marie Thérèse of France, Duchess of Angoulême; until her exile to the United Kingdom in 1830 
2. Queen Marie Amélie of France; as consort of Louis Philippe I beginning in 1830 until her exile in 1848
3. French State Treasury; during the French Second Republic 
4. Empress Eugénie of France; as consort of Napoleon III beginning in 1853 until her exile in 1870
5. French State Treasury; the tiara was kept at Brest, France from 1870 to 1872 along with the rest of the crown jewels and then moved to a vault at the Ministry of Finance, it was displayed at the 1878 Exposition Universelle and at the Musée du Louvre in 1884
6. Unknown Owner; the tiara was sold at auction with the rest of the crown jewels in May 1887 by the French Third Republic
7. Lady Aline Sassoon née Rothschild; a gift on the occasion of her 1887 marriage to Sir Edward Sassoon
8. Sybil Cholmondeley née Sassoon, Marchioness of Cholmondeley; inherited from her mother in 1909
9. Unknown Owner; sold at action at Christie's in 1973

Questions:

• Which jeweller altered the tiara?
• When was the tiara altered?
• Does the tiara still exist in it's second form?
• Who currently owns this tiara?