Arms of Stewart, Hereditary Stewards of Scotland (Or, a fess chequy argent and azure), with an inescutcheon Argent, a lion rampant gules, debruised by a bend raguly or. Augmentation to the arms of "Steward" given by the French King Charles VI (1368-1422) to Sir Alexander Steward "The Fierce", son of Andrew Stewart (by his wife the daughter of James Bethe), third son of  w:Alexander Stewart, 4th High Steward of Scotland (died 1283), from whose first son were descended all the Stuart monarchs of Scotland down to to Mary, Queen of Scots, and from whose second son were descended the remainder from King James I &amp; VI), for service done by his father Andrew Steward to that king and to the king of Scots, and also to John the French king, grand-father to Charles VI. 
These arms were engraved onto an ancient signet ring in the possession of w:Sir Richard Worsley, 7th Baronet (1751–1805), which at the request of w:Jeremiah Milles, Dean of Exeter and President of the Society of Antiquaries, was examined by John Charles Brooke, of the College of Arms, later Somerset Herald, who presented his report which was read in 1775 at the Society of Antiquaries, summarised below. (Source: Conjectures on Sir Richard Worseley's seal, published in Archaeologia: Or Miscellaneous Tracts Relating to Antiquity, 1777, pp.183-5[1])
Henry St George, Richmond Herald, when he conducted the Heraldic Visitation of Cambridgeshire in 1619 noted: "Charles VI, King of France, granted a patent to this Alexander, of the augmentation of his coat for service done by Andrew Steward, his father, to the said Charles and to the King of Scots, and also to John the French king, grandfather to Charles". (Clay, J. W., ed. (1897). The Visitation of Cambridge made in Anno 1575, continued and enlarged with the Visitation of the same county made by Henery St George, Richmond Herald, marshall and deputy to Willm. Camden, Clarenceulx, in Anno 1619, with many other descents added thereto. Harleian Society, 1st ser. 41. London, pp.7-11, pedigree of "Stuart" )
In "a large pedigree of the Stewards of Cambridgeshire" contained within a book in the College of Arms in London, "which deduces them regularly in a direct line from Banquo, Thane of Lochaber in the time of Duncan, King of Scotland", is written the following in Latin: (also quoted in: Clay, J. W., ed. (1897). The Visitation of Cambridge made in Anno 1575, continued and enlarged with the Visitation of the same county made by Henery St George, Richmond Herald, marshall and deputy to Willm. Camden, Clarenceulx, in Anno 1619, with many other descents added thereto. Harleian Society, 1st ser. 41. London, p.9 [2])
Alexander Styward unicus filius Andrea quem Carolus Rex Francorum auratae militiae symbola(m) (Visitation text: aurato milite symbolo) donavit una cum hoc honore ex armor(um) incremento ut tam ipse quam sui posteri in majori clypeo gentilitio aure super baram scaccatam minorem clypeum argenteum cum leone rapaci rubeo baculo aure nodofo oppressum amoris regi(a)e monumentum perpetuum deferrent sicut ex charta regia concessaria hic verbatim expresse apparetWhich may be translated:

Alexander Styward only son of Andrew whom King Charles of the French gave (a symbol of a golden knight ?) with this one honor from an incrementation of his arms that himself and his posterity likewise as him should bear as a perpetual monument of royal love just as this appears expressly verbatim from a royal charter of concession: on his large shield of gentility “a chequered bar above gold”,  a smaller shield “argent with a rapacious red lion crushed by a golden knotty club”The imagery alludes to the following event. An armed knight fought with a lion, and having broken his sword, which lay in fragments at his feet, snatched up a rude club with which he combatted the beast. In allusion to this, in some books the following crest is given to the Steward family A sword broken in two, the pieces placed in saltire on a wreath, and surmounting a ragged staff erecly or. 

Sir Alexander Steward "The Fierce" (whose existence has been questioned by some historians) and who is quoted in bogus ancient pedigrees as the ancestor of the English gentry family of "Steward" or "Styward", of the Isle of Ely in Cambridgeshire, from which family was the mother of Lord Protector Oliver Cromwell,[1][2][3] who (therefore ironically) tried to bring an end to the royal house of Stuart. However "the Lord Protector himself never took it seriously, though he did once joke that his mother was a Stuart at a drinking party in Edinburgh in 1651".[4] This family, of which the most influential was Robert Steward (d. 1557)  w:Dean of Ely, assumed the coat of arms of the Scottish Stewarts, Or, a fess chequy argent and azure, as is visible on their elaborate monuments in w:Ely Cathedral.[5] In addition they bore a supposed augmentation of honour (Argent, a lion rampant gules debruised by a bend raguly or) said to have been granted to Sir Alexander Steward "The Fierce" by King Charles VI of France (1380-1422).[6] However the supposed familial connection between the Stewart family of Scotland, Hereditary High Stewards and kings of Scotland (and thus with "Banquo, Thane of Lochaber in the time of Duncan, King of Scotland"), and the English "Steward" or "Styward" family of the Isle of Ely, has been definitively disproven by the renowned genealogists Horace Round (Studies in Peerage and Family History, 1907)[7][8] and Walter Rye (Two Cromwellian Myths, 1925, and The Steward Genealogy and Cromwell's "Royal Descent").[9]
own work, using File:AugmentedArms SirAlexanderSteward "TheFierce".svg by Lobsterthermidor (talk) 12:10, 29 November 2021 (UTC) (using lion from File:Heraldic Lion.svg by User:Wilfredor)
Lobsterthermidor (talk) 12:10, 29 November 2021 (UTC)