Question: Who is Roger Clifford, 5Th Baron Clifford's paternal grandmother?

Knowledge 1: Roger Clifford, 5th Baron Clifford
Roger de Clifford, 5th Baron de Clifford, ninth Lord Clifford, fifth Baron of Westmoreland (10 July 1333 – 13 July 1389), was the son of Robert de Clifford, 3rd Baron de Clifford (d. 20 May 1344), second son of Robert de Clifford, 1st Baron de Clifford (1273–1314), the founder of the northern branch of the family.His mother was Isabella (d. 25 July 1362), daughter of Maurice, 2nd Lord Berkeley.He succeeded his elder brother, Robert de Clifford, 4th Baron de Clifford in 1350, on which day he made proof of his age. [SEP] Knowledge 2: Robert Clifford, 3rd Baron Clifford
Robert de Clifford, 3rd Baron de Clifford, also 3rd Lord of Skipton (5 November 1305–20 May 1344) was a member of the Clifford family which held the seat of Skipton from 1310 to 1676.He was the second son of Robert de Clifford, 1st Baron de Clifford and Maud de Clare, eldest daughter of Thomas de Clare, Lord of Thomond and Juliana FitzGerald.His title was restored to him in 1327 after being forfeited by his elder brother Roger de Clifford, 2nd Baron de Clifford who was hanged for treason.He married Isabel de Berkeley, daughter of Maurice de Berkeley, 2nd Baron Berkeley at Berkeley Castle in 1328.They had 7 children.He was succeeded as Baron De Clifford by the eldest, Robert de Clifford, 4th Baron de Clifford
Knowledge 1: Robert Clifford, 3rd Baron Clifford
Robert de Clifford, 3rd Baron de Clifford, also 3rd Lord of Skipton (5 November 1305–20 May 1344) was a member of the Clifford family which held the seat of Skipton from 1310 to 1676.He was the second son of Robert de Clifford, 1st Baron de Clifford and Maud de Clare, eldest daughter of Thomas de Clare, Lord of Thomond and Juliana FitzGerald.His title was restored to him in 1327 after being forfeited by his elder brother Roger de Clifford, 2nd Baron de Clifford who was hanged for treason.He married Isabel de Berkeley, daughter of Maurice de Berkeley, 2nd Baron Berkeley at Berkeley Castle in 1328.They had 7 children.He was succeeded as Baron De Clifford by the eldest, Robert de Clifford, 4th Baron de Clifford [SEP] Knowledge 2: Thomas Percy (bishop of Norwich)
Thomas Percy was a medieval Bishop of Norwich.He was the son of Henry de Percy, 2nd Baron Percy and Idonia, daughter of Robert de Clifford, 1st Baron de Clifford.Percy was nominated 4 February 1355 and was consecrated on 3 January 1356.He died on 8 August 1369.
Knowledge 1: Roger Clifford, 5th Baron Clifford
Roger de Clifford, 5th Baron de Clifford, ninth Lord Clifford, fifth Baron of Westmoreland (10 July 1333 – 13 July 1389), was the son of Robert de Clifford, 3rd Baron de Clifford (d. 20 May 1344), second son of Robert de Clifford, 1st Baron de Clifford (1273–1314), the founder of the northern branch of the family.His mother was Isabella (d. 25 July 1362), daughter of Maurice, 2nd Lord Berkeley.He succeeded his elder brother, Robert de Clifford, 4th Baron de Clifford in 1350, on which day he made proof of his age. [SEP] Knowledge 2: Edward Southwell, 20th Baron de Clifford
Edward Southwell, 20th Baron de Clifford (6 June 1738 – 1 November 1777) was a British politician.

Answer: Maud de Clare