Richard de Clare, 5th Earl of Hertford, 6th Earl of Gloucester (4 August 1222 – 14 July 1262) was son of Gilbert de Clare, 4th Earl of Hertford and Isabel Marshal. On his father's death, when he became Earl of Gloucester (October 1230), he
was entrusted first to the guardianship of Hubert de Burgh. On Hubert's fall, his guardianship was given to Peter des Roches (c. October 1232) ; and in 1235 to Gilbert, earl Marshall
Richard's first marriage to Margaret or Megotta, as she was also called, ended with an annulment or with her death in November 1237. They were both approximately fourteen or fifteen. The marriage of Hubert de Burgh's daughter Margaret to Richard of Clare, the young Earl of Gloucester, brought de Burgh into some trouble in 1236, for the earl was as yet a minor and in the king's wardship, and the marriage had been celebrated without the royal license. Hubert, however, protested that the match was not of his making, and promised to pay the king some money, so the matter passed by for the time. Even before Margaret died, the Earl of Lincoln offered 5,000 marks to King Henry to secure Richard for his own daughter. This offer was accepted, and Richard was married secondly, on 2 Feb. 1238 to Maud de Lacy, daughter of John de Lacy, 1st Earl of Lincoln 
Richard had no children by his first wife, Margaret or Megotta de Burgh. By his second wife, Maud de Lacy, daughter of the Surety John de Lacy and Margaret de Quincy, he had:
Isabel de Clare, b. ca. 1240, d. 1270, m. William VII of Montferrat. Gilbert de Clare, b. 2 September 1243, d. 7 December 1295, 6th Earl of Hertford, 7th Earl of Gloucester. Thomas de Clare, b. ca. 1245, d. 1287, he seized control of Thomond in 1277; m. Juliana FitzGerald Bogo de Clare, b. ca. 1248, d. 1294. Margaret de Clare, b. ca. 1250, d. 1312, m. Edmund, 2nd Earl of Cornwall Rohese de Clare, b. ca. 1252, m. Roger de Mowbray Eglentina, d. 1257 in infancy.