four legitimized children of John of Gaunt by his mistress Katherine Swynford. King Henry IV, of the House of Lancaster, the son of John of Gaunt by his first wife Blanche of Lancaster, used a badge of a single ostrich feather entwined by a scroll inscribed with the motto "Ma Sovereyne". His eldest son and successor King Henry V used ostrich feathers as a secondary royal badge at various times, as did Henry IV's younger sons Thomas of Lancaster, 1st Duke of Clarence who used an ermine ostrich feather with a label; John of Lancaster, 1st Duke of Bedford who used an ostrich feather with the "Sovereygne" scroll; and Humphrey of Lancaster, 1st Duke of Gloucester who used an ostrich feather semée of fleurs-de-lis. Similar badges were used by other royal princes. House of Tudor The first Prince of Wales to use the badge in its modern form (i.e. three white feathers encircled by a coronet, and with the motto ) was Prince Arthur (1486–1502), eldest son of Henry VII, at the beginning of the 16th century. It was also widely used by Prince Edward, son of Henry VIII and afterwards Edward VI, although he was never formally invested as Prince of Wales. Feathers continued to be used as lesser royal badges, by Elizabeth I among others, until the end of the century. House of Stuart and successors Only from the beginning of the 17th century did the badge become exclusively associated with the Prince of Wales. It has formed the dexter badge of the heraldic achievement of the Prince of Wales since at least 1901, blazoned A plume of three ostrich feathers argent enfiled by a coronet composed of fleurs-de-lys and crosses patée or alternately with motto Ich Dien. Contemporary uses Military Several British military units have incorporated the Prince of Wales's feather into their badges. The feathers are featured on the cap badge of the Royal Welsh, an amalgamation of three Welsh regiments, the Royal Welch Fusiliers, the Royal Regiment of Wales and the Territorial Army's Royal Welsh Regiment. The badge of the Royal Navy's also incorporates the Prince of Wales's feathers. Other British military units that incorporate the Prince of Wales's feathers into their badge(s) include: 2 Squadron Honourable Artillery Company (squadron badge) Cheshire Yeomanry Princess of Wales' Royal Regiment (Queen's and Royal Hampshires) (cap badge) Royal Marines Band Service Commando Training Centre Lympstone (cap badge) Royal