Coat of arms of Robert de Vere, Duke of Ireland, Marquess of Dublin, 9th Earl of Oxford (1362-1392) (Sources: BELTZ, George Frederick, Memorials of the Order of the Garter from Its Foundation to the Present Time, London: William Pickering, 1841; FOSTER, Joseph, Some Feudal Coats of Arms from Heraldic Rolls 1298-1418, London; &amp; Oxford: James Parker &amp; Co., 1902). Quarterly of 4:

1&amp;4: Azure, three crowns or a bordure argent (grant of augmentation by King Richard II, grant 3 Jan. 1386, pat. I. m. 1 Cotton MS. Julius C. VII fo. 237 (source: FOSTER, Joseph, Some Feudal Coats of Arms from Heraldic Rolls 1298-1418, London; &amp; Oxford: James Parker &amp; Co., 1902))
2&amp;3: Quarterly gules and or, in the first quarter a mullet argent (de Vere)
Own work (User:Thom.lanaud) + elements from User:Sodacan
User:Thom.lanaud