How much of the English history in this Decameron story has any basis in fact?

Question

Day 2 Story 3 of the Decameron is a story which deeply involves the English royal family. I don't know how much contact there was between England and Italy in the 14th century, or how much care an Italian writer of that time would have been expected to take in providing accurate historical information about foreign countries, but how much of the described English events have any basis in real history?

• There is a war between the English king and his son, which lasts for several years:

  While the three brothers thus continued to spend freely, and, when short of money, to borrow it, never doubting of help from England, it so happened that, to the surprise of everybody, there broke out in England a war between the King and his son, by which the whole island was divided into two camps; whereby Alessandro lost all his mortgages of the baronial castles and every other source of income whatsoever. [...] Alessandro, meanwhile, seeing that the peace, which he had for several years awaited in England, did not come, and deeming that he would hazard his life to no purpose by tarrying longer in the country, made up his mind to return to Italy.

• A daughter of the English king travels to the pope in Rome, disguised as an abbot, in order to escape marriage to the king of Scotland:

  “Holy Father, as you must know better than any other, whoso intends to lead a true and honourable life ought, as far as may be, to shun all occasion of error; for which cause I, having a mind to live honourably, did, the better to accomplish my purpose, assume the habit in which you see me, and depart by stealth from the court of my father, the King of England, who was minded to marry me, young as you see me to be, to the aged King of Scotland; and, carrying with me not a little of his treasure, set my face hitherward that your Holiness might bestow me in marriage. Nor was it the age of the King of Scotland that moved me to flee so much as fear lest the frailty of my youth should, were I married to him, betray me to commit some breach of divine law, and sully the honour of my father's royal blood.

• She marries an Italian (one of the major characters of this story) who becomes the earl of Cornwall and later, perhaps, the king of Scotland:

  The two knights went before them to England, and by their influence induced the King to restore the lady to his favour, and receive her and his son-in-law with every circumstance of joy and honour. Alessandro he soon afterwards knighted with unwonted ceremony, and bestowed on him the earldom of Cornwall. And such was the Earl's consequence and influence at court that he restored peace between father and son, thereby conferring a great boon on the island and gaining the love and esteem of all the people. Agolante, whom he knighted, recovered all the outstanding debts in full, and returned to Florence immensely rich. The Earl passed the rest of his days with his lady in great renown. Indeed there are those who say, that with the help of his father-in-law he effected by his policy and valour the conquest of Scotland, and was crowned king of that country.

I'm fairly sure that at least the last of these points doesn't have any basis in reality, but maybe the first one does.

Answer 1

One of the notes to number 14 in BUR version of the Decameron (Italian original), edited by Amedeo Quondam, Maurizio Fiorilla and Giancarlo Alfano, explains that the first of your points refers to the war between the king Henry II of England (1133-1189) and his eldest son Henry, called the "Young King" (1155-1183), broken out in 1173:

nacque … figliuolo: il tono genericamente allusivo richiama la guerra tra Enrico II Plantageneto (1133-1189) e suo figlio primogenito Enrico detto il Giovane (1155-1183), scoppiata nel 1173;

You can find some information about this war in this video.

As for the historical background of the other two points you mention, in this book only a note to number 37 says that this Pope was possibly Alexander III. There isn't any other allusion of historical events in the notes to the paragraphs of this novella that tell the facts you have described, which seems to me an indication that, as you say, these two points doesn't have any basis in History.

As regards the possibility, mentioned by you in a comment, that the latter part of the story could be inspired by the life of Henry II's granddaughter Joan, I have also read the notes to this novella in other two Italian original versions of the Decameron, the one published by Einaudi, edited by Vittore Branca, and the one published by Feltrinelli, edited by Marco Veglia, and none of them said nothing about this.

In fact, Vittore Branca says in his book:

La romanzesca vicenda narrata in questa novella – che sarà subito imitata nel Pecorone (III 1) – non ha nessun vero antecedente né letterario né storico (di scarsissimo valore i richiami alla chanson del Conte di Fiandra: cfr. Histoire littéraire de la France, XXIV, p. 167; e anche alla Chronica di Guillaume de Nangis, ed. Geraud, Paris 1843, II, pp. 209 sgg.). Non è in sostanza che una variazione sulla bella e canonica fiaba del giovane che fa la sua fortuna conquistando, quasi senza neppure conoscerla, il cuore della reginotta: una fiaba amata e ripetuta dal B. (cfr. B. medievale, pp. 199 sgg.) e appartenente a moduli antichissimi (J. G. FRAZER, The golden bough, I 2,3; V. J. PROPP, Le radici storiche ecc, cap. IX, 11; Thompson e Rotunda, L 160, 161; T 55.1, 91.4, 121).

My translation:

The novel events narrated in this short story - which will immediately be imitated in Pecorone (III 1) - have no real antecedent, neither literary nor historical (the references to the chanson of the Count of Flanders are of very little value: see Histoire littéraire de la France, XXIV, p. 167; and also to the Chronica by Guillaume de Nangis, ed. Geraud, Paris 1843, II, pp. 209 ff.). It is essentially a variation on the beautiful and canonical fairy tale of the young man who makes his fortune by conquering, almost without even knowing her, the queen's heart: a fairy tale loved and repeated by Boccaccio (cf. Boccaccio medievale, pp. 199 ff.) and belonging to very ancient modules (JG FRAZER, The golden bough, I 2,3; VJ PROPP, Le radici storiche etc., chap. IX, 11; Thompson and Rotunda, L 160, 161; T 55.1, 91.4, 121).

And also:

Chi dovrebbe essere questo re di Scozia è difficile dire (vedi 48 n.); forse Guglielmo il Leone (1143-1214)? il quale, però, ai tempi in cui è immaginata l’azione della novella, cioè prima della morte di Papa Alessandro III (1181), non era vecchissimo. Il re d’Inghilterra sarà logicamente Enrico II: ma tutti i dati sono favolosamente mescolati.

My translation:

Who this king of Scotland should be is difficult to say (see 48 n.); perhaps William the Lion (1143-1214)? who, however, at the time when the action of the story is imagined, that is, before the death of Pope Alexander III (1181), was not so old. The king of England will logically be Henry II: but all the data are fabulously mixed.