As Wolff has rightly noted,‘the inference is strong that, in Castile, these
three were amongst the most prominent courtiers of [King] Alfonso, just
as, when in France, they also were of St Louis’.^33 Moreover, we know
that at least one of the brothers served the king of Castile in war as well.
In the mid-1260s, Alfonso of Brienne took part in the‘crusade against
themudéjars’: that is, against the Moors of Murcia and Granada, who
could call on assistance and reinforcements from North Africa. Alfonso’s
involvement was sufficiently noteworthy that it earned him a congratu-
latory letter from the pope.^34 Most importantly, though, the Briennes
managed to carve out a diplomatic niche for themselves,flaunting their
usefulness in the sphere of Franco-Iberian relations. In July 1262,
Alfonso and John of Brienne were amongst the witnesses to an oath
sworn by King James of Aragon, at the request of Louis IX, that he
would not assist Frederick II’s illegitimate son and heir, King Manfred of
Sicily. Yet this was the start, not the end, of the Briennes’involvement in
this thorny matter–and it would give rise, in due course, to the‘War of
the Sicilian Vespers’.^35
The Briennes’success was not merely confined to their most obvious
royal kin. Bolstered by the beginnings of Anglo-Frenchrapprochementin
the mid-thirteenth century, it seems that this was the period when they
began to mend their relations with the English crown.^36 There were
some difficulties atfirst, especially after the marriage of John of Brienne
to Mary, the dowager queen of Scots. Naturally enough, this raised fears
about a further extension of French influence over Scotland, but there
was, in fact, little reason to worry about this. Despite their position as
nominal heads of the regency council in the late 1250s, John and Mary
had a surprisingly limited role in Scottish politics over the course of this
period.^37 It has been suggested that, in the aftermath of early contacts
such as these, John forged an accord with the future Edward I, whom he
accompanied back to England in the early 1260s.^38 However, this is
based on a misreading of the evidence. It was Edward’s new brother-in-law,
(^33) Wolff,‘Mortgage and Redemption of an Emperor’s Son’, 76.
(^34) SeeLes registres de Clement IV, 1265–68: recueil des bulles de ce pape, ed. É. Jordan, 6 vols.
(Paris, 1893–1945), i, no. 1028.
(^35) Wolff,‘Mortgage and Redemption of an Emperor’s Son’,55–6, 76.
(^36) For the relationship between the two dynasties, see S. Lloyd,English Society and the
Crusade, 1216– 1307 (Oxford, 1988), 32.
(^37) SeeThe Acts of Alexander III: King of Scots, 1249– 1286 , compiled by C. Neville and
G. Simpson (Edinburgh, 2012), no. 196; M. Campbell,Alexander III: King of Scots,Isle
of Colonsay, 1999), 83–90, 103, 107; and M. Brown,The Wars of Scotland: 1214– 1371
(Edinburgh, 2004), 44–56, 140–1. However, much of the above should be treated with
38 caution for what it has to say about the Briennes.
D’Arbois de Jubainville,Histoire, iv, part 1, 450.
82 In the Pages of Joinville (c. 1237–1267)