Question: Who is Maud De Clare's paternal grandfather?

Knowledge 1: Maud de Clare
Maud de Clare, Baroness de Welles was the eldest daughter of Thomas de Clare, Lord of Inchiquin and Youghal, Lord of Thomond, Lord of Bunratty Castle (1245–1287) and Juliana FitzGerald (1236–1290).She married two times.Her first marriage was to Robert de Clifford, 1st Baron de Clifford, 1st Lord of Skipton (1274–1314) on 3 November 1295 by which she had four children.Her second marriage was to Sir Robert de Welles, 2nd Baron Welles, Constable of Pendragon Castle (1297–1326) on 16 Nov 1315.They had no children.She was born in 1276 in Tewkesbury, Tewkesbury Hundred, Gloucestershire, England and moved to Badlesmere to be near her sister, Margaret de Clare, Baroness Badlesmere.She died in Badlesmere in 1327 twice a widow. [SEP] Knowledge 2: Thomas de Clare, Lord of Thomond
Thomas de Clare, 1st Lord of Thomond, 1st Lord of Inchiquin and Youghal (1244×124729 August 1287) was a Hiberno-Norman peer and soldier.He was the second son of Richard de Clare, 6th Earl of Gloucester and his wife Maud de Lacy, Countess of Gloucester.In 1272 he served a term as Lieutenant of the Duchy of Aquitaine.On 26 January 1276 he was granted the Lordship of Thomond by Edward I of England; he spent the next eight years attempting to conquer it from the O'Brien dynasty, kings of Thomond.
Knowledge 1: Maud de Clare
Maud de Clare, Baroness de Welles was the eldest daughter of Thomas de Clare, Lord of Inchiquin and Youghal, Lord of Thomond, Lord of Bunratty Castle (1245–1287) and Juliana FitzGerald (1236–1290).She married two times.Her first marriage was to Robert de Clifford, 1st Baron de Clifford, 1st Lord of Skipton (1274–1314) on 3 November 1295 by which she had four children.Her second marriage was to Sir Robert de Welles, 2nd Baron Welles, Constable of Pendragon Castle (1297–1326) on 16 Nov 1315.They had no children.She was born in 1276 in Tewkesbury, Tewkesbury Hundred, Gloucestershire, England and moved to Badlesmere to be near her sister, Margaret de Clare, Baroness Badlesmere.She died in Badlesmere in 1327 twice a widow. [SEP] Knowledge 2: Robert de Welles, 2nd Baron Welles
Robert de Welles, 2nd Baron de Welles, Constable of Pendragon Castle was the son of Adam de Welles, 1st Lord of Welles( 1249 – 1311) and Joan d'Engayne( 1265 – 1315).He married Maud de Clare, daughter of Thomas de Clare, Lord of Thomond( 1245 – 1287) in 1315 without royal licence.It is said that he did, in fact, have a daughter by Maud de Clare, but historical evidence remains elusive.The Barony de Welles passed to his brother, Adam de Welles, 3rd Baron Welles( 1304 – 1345) on his death.He is buried at Greenfield Priory, Greenfield, East Lindsey District, Lincolnshire, England.
Knowledge 1: Maud de Clare
Maud de Clare, Baroness de Welles was the eldest daughter of Thomas de Clare, Lord of Inchiquin and Youghal, Lord of Thomond, Lord of Bunratty Castle (1245–1287) and Juliana FitzGerald (1236–1290).She married two times.Her first marriage was to Robert de Clifford, 1st Baron de Clifford, 1st Lord of Skipton (1274–1314) on 3 November 1295 by which she had four children.Her second marriage was to Sir Robert de Welles, 2nd Baron Welles, Constable of Pendragon Castle (1297–1326) on 16 Nov 1315.They had no children.She was born in 1276 in Tewkesbury, Tewkesbury Hundred, Gloucestershire, England and moved to Badlesmere to be near her sister, Margaret de Clare, Baroness Badlesmere.She died in Badlesmere in 1327 twice a widow. [SEP] Knowledge 2: Kaya Alp
Kaya Alp was, according to Ottoman tradition, the son of Kızıl Buğa and the father of Suleyman Shah, who was, in turn, the grandfather of Ertuğrul, and the great grandfather of the Ottoman Empire founder, Osman I.

Answer: Richard de Clare, 6th Earl of Gloucester