not dead, just on holidays

From the ODNB biography of Edward II (1284-1327) -

Although the official account said that Edward had died of natural causes, it was soon widely believed that he had been murdered. Murder is the most likely cause, perhaps following a conscious decision by Mortimer to rid himself of the embarrassment of a former king, or even in a moment of panic by Edward's gaolers when yet another attempt to free him was reported. However, a natural death, possibly from a pre-existing and painful condition (which might account for the lurid chronicle accounts of his death) or from ill treatment or from the mental shock of his deposition, should not be ruled out. But it was also rumoured that Edward had after all escaped from Berkeley, so much so that in March 1330 Edward's half-brother, Edmund, earl of Kent, was executed for plotting to restore the late king. In September 1330 the pope wrote to the king and to Isabella expressing amazement that anyone could believe 'that he, for whom solemn funerals had been made, could still be alive' (CEPR letters, 2.499).

In September 1338 a certain William le Galeys ('the Welshman') appeared at Cologne claiming to be Edward II and was escorted to Koblenz where Edward III was then meeting the emperor, Ludwig of Bavaria. This episode may have some connection with the astonishing letter preserved in a fourteenth-century register of the French diocese of Maguelone (now Montpellier) and apparently written to Edward III between 1336 and 1338 or at the latest 1343 by Manuele Fieschi, an Italian cleric with good connections both with the English court and the papal curia who ended his career as bishop of Vercelli in Italy. According to this, Edward had wandered across Europe after his escape, visiting Ireland, England, Normandy, Avignon, Paris, Brabant, Cologne, and Milan, before ending his days as a hermit at Cecima, near Voghera in Lombardy. A tomb of earlier date which is wrongly claimed to be that of Edward II can even be seen in the nearby abbey of Sant'Alberto di Butrio. Although there is no reason to believe that the circumstantial story told in the Fieschi letter is based on fact, the mystery remains of how and why the letter came to be written.

If some believed that Edward lived on after 1327, others wished to present him as a candidate for canonization. Such feelings were probably inspired both by a desire to counter the moves to canonize Edward's former opponent, Thomas of Lancaster, and by the rumours about the hideous mode of Edward's death - his bowels burnt out with a red-hot spit or poker inserted at his anus - which were given literary expression by the unknown author of the Brut chronicle and by Geoffrey Baker. Some of Edward's old allies and sympathizers among the Dominican order may also have played a part. There is no evidence of any systematic attempt to have Edward canonized until Richard II petitioned the pope in 1385; a book of Edward II's miracles was compiled and presented to Pope Boniface IX at Florence early in 1395. The process however lapsed with Richard II's own deposition in 1399, never to be resumed.