There were two Robert Williams associated with the Grenvilles, one an aristocratic MP and the other a friend of the young Richard Temple. 

Sir Robert Williams

1764-1830. Sir Robert Williams (9th Baronet) was a Genvillite MP for Caernarvonshire. He was half brother, heir and parliamentary representative to Thomas James, seventh Viscount Bulkeley. 

• 1764: Born 20 July 
• 1799: 11 June married Anne (?-1837), daughter of Rev Edward Hughes, of Kinmel Park, Denbighs
• 1790–1826: MP for Caernarvonshire  
• 1826–30: MP for Beaumaris 
• 1830: Died 1 December

Williams often voted at Bulkeley's command but disliked attending Parliament. When the Grenvillites voted against the Treaty of Amiens in May 1802, he voted in favour of the treaty and did not return to the Grenville line until Pitts death in January 1806. He was opposed to catholic emancipation and a strong supporter of the protestants who fought against consideration of the question. By 1817 he was aligned with the Whigs.

He was a member of Brooks's Club.

Robert Williams

This Robert Williams was a Captain in the army in Ireland in 1791 and a friend of Richard Temple and William Henry Fremantle (BRO FR/54/1). He was a bawdy young man and sexually active.

In 1792, he went to Oxford University:

Williams, Robert son William of Bangor, Co Glamorgan pleb Jesus College, matric. 31 March 1792, aged 21, B.A. 1795, M.A. 1798 (Foster)