Anne Eliza was daughter of Richard Gamon and Elizabeth Grace. 

She first married Roger Hope Elletson, Lieutenant Governor of Jamaica from 1766–68, who died in 1775. They had no children.

At his death, Anne Eliza inherited the Hope plantation in Jamaica and managed it as an absentee planter (see Sturtz: DimDuke).

Her second marriage in 1777 was to James Brydges, the 3rd Duke of Chandos. 

James and Anne Eliza had two children:

• Georgiana Chandos, who died in infancy. 
• Anna Elizabeth (Eliza), who inherited her parent’s estates. She was later the first Duchess of Buckingham and Chandos.

Anne Eliza was a "vain and extravagant woman, of great animal spirits, who caused her husband’s death in 1789 by thrusting aside the chair in which he was about to sit down. She was extremely attached to him, and became in consequence insane until her death in 1813." [quoted from Temple Memoirs]

Anne Eliza was certified a lunatic in 1791. She had written her will in 1789. She was well enough to attend her daughter's wedding in April 1796 but in October 1798, she nearly died of an accidental drug overdose:

The poor Duchess dowr has had a narrow escape of her life by swallowing linniment (in wch were 150 drops of Laudanum) instead of a Saline draught, Strong Emeties & perpetual motion to keep her awake saved her life, & she is now recovered. (Lady Caroline Leigh to Anna Eliza Brydges, 13 October 1798; HEH STG Correspondence Box 8 (01))

Anne Eliza died on 19 January 1813 at Chandos House, although for much of her lunacy she lived at Minchendon. Her death was unexpected:

Poor Gamon is in a wretched state and disarms all resentment. The Duchess never was conceived by the Physicians to be in any danger, as the attack began in nothing more than a cold, and that not attended with more fever than belongs to a cold. She never was put to bed, and her pulse good to the last, when certainly some apoplectic seizure took place as she died in a state of coma, and without a struggle. So little was she considered in danger that Monro was anxious to dismiss Milman who had been called in, from all attendance on Tuesday night, and upon Gamon’s asking him whether he thought there was any thing to be apprehended, he said that whilst pulse was as good as it then was, she would never die — and left her. (Richard Temple to Nugent Buckingham. HEH STG Correspondence Box 34 (38); 1813/01/22.)

Her estate was settled in 1816, and her daughter, Anna Eliza inherited an estate worth £6,500 a year from English and Irish estates, as well as the Jamaican estates.

See also: The Family Tree