28 April 1313: Edward orders the release of Isabel MacDuff, countess of Buchan, who had crowned Robert Bruce king of Scotland in 1306, into the custody of his kinsman Henry Beaumont. This is the last mention of Isabel that I know of; she is not named among the Scottish hostages released after Bannockburn the following year.
28 April 1317: Wedding of Margaret de Clare and Hugh Audley at Windsor Castle, in Edward's presence.
27 April 1318: Edward writes to Pope John XXII asking his permission to found a house of Dominican nuns at Langley Priory, which he had founded in 1308. Sadly, nothing came of this until 1349, when Edward III finally established a sisters' house there. (Nice to see Edward III taking an interest in his father's foundation.)
25 April 1284: Birth of Edward II at Caernarfon.
25 April 1287: Birth of Roger Mortimer, lord of Wigmore and earl of March.
25 April 1295: Death of Edward's first cousin Sancho IV of Castile.
25 April 1309: Pope Clement V gives Edward an excellent twenty-fifth birthday present by agreeing to lift the excommunication on Piers Gaveston.
24 April 1316: Edward II asks the Dominicans of Toulouse to pray for him (something he did fairly often, also asking the Dominicans of Pamplona, Marseilles, Paris, Rouen, Citeaux, Florence, Venice, Barcelona and Vienna to say prayers "for the good estate" of himself, Queen Isabella and their children at various times over the years).
23 April 1307: Death of Edward's sister Joan of Acre, countess of Gloucester.
22 April 1355: Death of Edward's elder daughter Eleanor of Woodstock, dowager duchess of Gelderland, at the age of thirty-six. Duchess Eleanor was buried at Deventer Abbey. She left two sons: Duke Reinald III of Gelderland, then not quite twenty-two, and the future Duke Eduard of Gelderland, then nineteen.
20 April 1314: Pope Clement V, born Raymond Bertrand de Got, dies in Avignon, a month and two days after Jacques de Molay, last Grand Master of the Knights Templar, supposedly curses him from the flames of his execution pyre.
20 April 1315: Edward II holds a great banquet for the archbishop of Canterbury and most of the nobility at Westminster Hall, which is damaged by a fire shortly afterwards.
17 April 1290: At Amesbury Priory in Wiltshire, Gilbert 'the Red' de Clare, earl of Gloucester, signs an agreement with his soon-to-be father-in-law Edward I, acknowledging that after the king's death he will recognise Edward of Caernarfon (not quite six years old) as his liege lord, and, if Edward I dies without fathering more sons and Edward of Caernarfon dies without heirs of his body, then the king's eldest surviving daughter Eleanor will be rightful heir to the throne.
17 April 1306: Edward gives ten shillings each to the watchmen who rouse him from his bed and evacuate his household as flames swept through Windsor Castle.
17 April 1320: Pope John XXII canonises Thomas Cantilupe, bishop of Hereford, who had died in August 1282. This was due in part to the efforts of Edward II himself, who wrote to Clement V and John XXII half a dozen times between December 1307 and January 1319, asking them to canonise Cantilupe.
15 April 1318: Edward’s brother-in-law Philip V of France (who succeeded to the throne in November 1316) accepts Edward’s excuses for not travelling to France to perform homage for Gascony and Ponthieu and grants him permission to appoint envoys to do homage on his behalf, around the time of the Nativity of St John the Baptist, or 24 June. Edward manages to put off the dread moment of kneeling to another person until late June 1320.
15 April 1324: The final date by which Edward is meant to perform homage to yet another brother-in-law, Charles IV. His failure to do so precipitates the last great crisis of his reign.
15 April 1326: Edward II informs his kinsman Afonso IV of Portugal that his son Edward will be unable to marry Afonso's daughter Maria, as the Portuguese king has suggested, as the boy is betrothed to Leonor of Castile. (And ultimately marries Philippa of Hainault.)
14 April 1322: Execution of Bartholomew, Lord Badlesmere, formerly steward of Edward II's household, who took part in the Contrariant rebellion against the king and was captured by Donald of Mar at one of the manors of his nephew the bishop of Lincoln. Bartholomew is dragged the three miles from Canterbury to the crossroads at Blean, hanged, drawn and quartered - one of only three men I know of who suffered the traitor's death during Edward II's reign, the others being Sir Gilbert Middleton and Hugh Despenser the Younger (and the latter was not done at Edward's order, of course). Poor man; no-one deserves to die like that.
13 April 1326: Edward tells the archbishop and prior of Canterbury and the abbot of St Augustine’s that "an invasion of the realm by aliens is threatened," i.e. his queen and Mortimer's invasion.
10 April 1315: Edward passes legislation ordering the price of various basic foodstuffs to be fixed and regulated in an attempt to mitigate his subjects' misery during the Great Famine.
8 April 1314: Edward spends Easter Monday at Ely Cathedral, quizzing the monks as to their supposed possession of the body of St Alban when he'd just seen it in St Albans Abbey. Heh. "You know that my brothers of St Albans believe that they possess the body of the martyr. In this place the monks say that they have the body of the same saint. By God’s soul, I want to see in which place I ought chiefly to pay reverence to the remains of that holy body."
7 April 1323: Edward orders an inquiry into the recent near-escape of several Contrariants from Wallingford Castle.
4 April 1284: Death of Edward's uncle Alfonso XI of Castile, exactly three weeks before Edward was born.
4 April 1311: An anonymous letter-writer says that "a secret illness troubles [Piers Gaveston] much, compelling him to take short journeys."
3 April 1327: Custody of the former King Edward II is transferred from his cousin Earl Henry of Lancaster at Kenilworth Castle to Thomas, Lord Berkeley, Sir John Maltravers and Sir Thomas Gurney at Berkeley Castle.
2 April 1318: Robert Bruce seizes the port of Berwick-upon-Tweed, following several unsuccessful attempts. Edward's efforts to take it back the following year end in embarrassing failure and it remains in Scottish hands until Edward III recaptures it in July 1333.
1 April 1312: Edward pretends in a letter to his father-in-law Philip IV of France that he is hurrying to Berwick-upon-Tweed, which Robert Bruce is currently besieging, when he is in fact far too concerned with Piers Gaveston's safety to do any such thing. He fails to mention that his own men are holding the Scottish border against him to prevent him sending Piers there.