A New and Legal Pun in Chaucer by Bartholomew Lee, 89 The Law Quarterly Review 345 [Volume 89 July 1973, London – complete]
A Somonour was ther with us in that place,
That hadde a fyr-reed cherubynnes face
General Prologue to the Canterbury Tales, lines A624-25.
The common law writ of fieri facias, which antedates Chaucer by more than a century  persists to this day.  A noted commentator on legal language has remarked “the red-faced sound of this writ has inspired legal puns at least since the end of the sixteenth century.”  The writ executes the judgment of a court in a lawsuit; through it the judge directs the sheriff to sell property belonging to the defendant, to make up the fund that will pay the award the plaintiff has won. The fieri facias takes its name from the phrase “cause there to be made.” A writ roughly contemporaneous to Chaucer’s study of the law (i.e., writs) as a young man  will illustrate:
“The king to the sheriffs of London, greeting. We command you that without delay you cause execution to be made [fieri faciatis] of the judgment lately rendered in our court of London in a plea which was in our court without our writ between A. and B. concerning a debt of twenty shillings which the said A. demands from the aforesaid B. Witness.” 
This writ is substantially the writ Chaucer had to fear in the Trespass and Contempt suit he defended and settled in 1379 ; the fieri facias in general came to be the bane of defendants in general in Chaucer’s litigious era.
The summoners of the medieval period formed a numerous class of officers in both the ecclesiastical and the common law courts. They summoned defendants to court: summone per bonos summonitores is one of the commoner phrases in common law writs.  Common law summoners acted as sheriffs’ bailiffs as late as Blackstone.  As summoners, at least as early as the fourteenth century, they fulfilled their office by serving defendants with notice of a lawsuit, legal processes, and copies of writs.  One particular writ known as the Significavit provided any ecclesiastical summoner of extortionate bent with a potent threat. Defiance of the summoner’s demands could ultimately result in Chancery issuance of this writ, and arrest and imprisonment.  Chaucer warns of this writ in his description of the Summoner (A662).
However similar or distinct the duties of summoners to common law and ecclesiastical courts may have been, in the initial lines of Chaucer’s description of the Summoner, it is unclear which court system he serves. Chaucer simply presents a Somonour who bears a fyr-reed …face, making his affiliation explicit only after the description of his affliction – the disease which makes him so saucefleem that children feared his visage.
The poet’s propensity for puns and related word play has recently been persuasively demonstrated.  In the two opening lines of the Summoner’s description (A Somonour was ther with us in that place, that hadde a fyr-reed cherubynnes face) he has described the Pilgrim whose office most closely associates him with the bearing of writs, with a play on the name of one of the leading writs of the day – the fieri facias. The description of the Pilgrim’s disease no doubt reflects back upon the writ. The fyr-reed …face that the Summoner bore might be too horrid to contemplate; but just so horrid would be a debtor’s contemplation of the fieri facias by which the sheriff sold his substance. The several lawsuits against Chaucer in the period 1388-98, for Debt,  evidence the probability of Chaucer’s awareness of the personal relevance of the writ.
To the educated and legally knowledgeable members of Chaucer’s audience, the implications of the pun would not be lost: the writ could only be unpleasant to have to face. The adjective cherubynnes, while it adds something to the Summoner’s ultimately ecclesiastic connections, also adds a tinge to the pun. Medieval artists consistently painted their cherubim with flame coloured faces.  The Oxford English Dictionary supplies a curious early (1611) dictionary definition: “. ..cherubin-faced, having a fierie facies like a cherubin.” 
1. Dr. Elsa de Haas and G. D. G. Hall (eds.), Early Registers of Writs, Publications of the Selden Society, Vol LXXVII., (London, 1970), at p. 325, present a fieri facias from a Register of writs dating from the middle of the thirteenth century.
2. See Rules of the Supreme Court, Order 45, and J. H. Koffler and R. Reppy, Handbook of Common Law Pleading, (St. Paul, Minn., 1969), p. 595, for the position in America.
3. David Mellinkoff, The Language of the Law (Boston, 1963), p. 76, citing the Oxford English Dictionary, (fieri facias, b) which supplies” 1594 [Thomas] Nashe Unfort[unate] Trav[eller] , Works ([London,] 1601) V: 44 Purseuants [i.e., plaintiffs in law suits] with red noses. ..a pursuant. ..with the verie reflexe of his firie facias.”
4. J. M. Manly, Some New Light on Chaucer (New York, 1926), pp. 7-18.
5. Haas and Hall, op. cit., p. 116. This writ dates from the first third of the fourteenth century.
6. Martin M. Crow and Clair C. Olson (eds.), Chaucer Life Records, (Oxford, 1966), pp. 340-342.
7. Haas and Hall, op. cit., p. xii n. 4, place the first great flourishing of the common law writs well into the fourteenth century.
8. M. M. Bigelow, History of Procedure in England, (Boston, 1880), p. 223.
9. See, e.g., Haas and Hall, op. cit., p. 318.
10. Sir William Blackstone, Commentaries on the Laws of England, (Oxford, 1770) 3:279.
11. W. C. Bolland (ed.), Yearbooks 7 Edw. II (1813-14), Publications of the Selden Society, Vol. XXIX, (London, 1922), p. xi.
12. Muriel Bowden, A Commentary on the General Prologue to the Canterbury Tales, 2nd ed. (London, 1967), pp. 267-268.
13. See, e.g., Helge Kokeritz, “Rhetorical Word Play in Chaucer,” PMLA 69 (1954): 937; and Paull F. Baum, “Chaucer’s Puns,” PMLA 71 (1956): 225.
14. The writs and documents appear in Crow and Olson, op. cit., pp. 384-401.
15. Nevill Coghill, trans., The Canterbury Tales, (Baltimore, 1963), p. 509.
16. Oxford English Dictionary, (cherub, 5), quoting Randle Cotgrave, A Dictionarie of the French and English Tongues (London (?), 1611).