He was the son of John Juhyne, a wool merchant from Bristol, by his wife a certain Margery.
Career
Following the death of his father in 1390, Juyn inherited his estates in Bristol, Bedminster and Knowle. His father's contacts with the Bristolian merchant community helped with his career; between 1422 and 1438 he served as Recorder of Bristol, and also acted as a feoffee for many of the city's leading merchants. His first appearance in surviving records was in 1407, as a mainpernor for a group of Bristolian merchants sued for debt by the City of London. He was appointed a serjeant-at-law in 1415, but avoided taking-up this position and its financial burden until 1418. Between 1416 and 1422 he served as legal counsel for the Duchy of Lancaster, settling the matter of the Bohun estate, dividing it between King Henry V and Lady Anne Hastings, and also served as counsel to Thomas of Lancaster, 1st Duke of Clarence between 1418 and 1420. He travelled the Western circuit as a Justice of Assizes between 1422 and 1424. On 5 May 1423 he was appointed Lord Chief Baron of the Exchequer. In 1436 he received an additional appointment as Justice of the Court of Common Pleas, from which time he switched to the Home Counties circuit. In May 1426 he was knighted in Parliament, and acted as a trier of petitions there from 1425 to 1439, during which period he was summoned frequently to advise the King's Council, most notably for 15 days at the November 1426 Council at Reading, where he helped to draft laws to keep the peace between Humphrey, Duke of Gloucester and Henry Beaufort. For most of his life he lived in Somerset, in which county he served as a Justice of the Peace on every Peace Commission between 1419 and his death. He raised loans for King Henry IV in the 1420s and 1430s. On 9 February 1436 he was appointed Chief Justice of the Common Pleas, still retaining his position as Lord Chief Baron of the Exchequer, and on 20 January 1439 he was made Chief Justice of the King's Bench, when finally he quitted his joint positions in the Courts of Exchequer and Common Pleas. He held this position for only a year before becoming ill, and died on 24 March 1440.
Marriages and children
He married twice:
Firstly to a certain Edith, who died childless;
Secondly to Alis Moore, a daughter of Nicholas de la Moor, of Moor Hayes in the parish of Cullompton, Devon, by whom he had two daughters and co-heiresses:
