These extracts are from the "Calendar of Papal Letters to Scotland of Clement VII of Avignon 1378-1394" edited by Charles Burns, publ. Scottish History Society, Edinburgh 1976.

References to Reg Aven show the volume and folio number of the Registers of Avignon in the Vatican Archives. Fondi was where Pope Clement VII was crowned in 1378 and Avignon was where he resided for the rest of his life, this being the period of the Great Schism between rival papacies in Avignon and Rome. England supported the Roman Pope so naturally Scotland sided with Avignon!

17 November, 1378
Reg Aven 205, 505v-6v
To the official of St Andrews. Mandate to provide Symon de Crech, M.A., also said to be proficient in canon law, rector of the parish church of Cullas, St Andrews diocese, to a canonry of Dunkeld with expectation of a prebend, provided he resigns his parish upon obtaining possession of a parsonage, or office, with cure, but notwithstanding that he holds the perpetual chaplaincy of the chapel of Forgundenyny, Dunkeld diocese.
Fondi, 15 Kal. Dec., anno 1.

28 November, 1384
Reg Aven 240, 23
To Walter, cardinal priest of Holy Roman Church. Mandate to enquire into the circumstances surrounding the resignation of abbot John of Abubronthoch Abbey, O.S.B., St Andrews diocese, for reasons of advanced old age, made into the hands of Pierre, cardinal priest of S. Marco, by Simon de Creych of St Andrews diocese, the abbot's proxy, after several witnesses had been heard on the matter at the papal Curia. If the reasons are found to be valid, the cardinal is to confirm this resignation and to provide John Gedy, priest and professed monk of the said monastery, to the office of abbot, as was desired by abbot John himself, with permission for the solemn blessing to be imparted on the new abbot by any bishop in communion with the Apostolic See, to whom the oath of fidelity must be made, and then, duly sealed, transmitted with all care to the pope.
Avignon, 4 Kal. Dec., anno 7.

6 October, 1386
Reg Aven 243, 303v-4
To the abbot of Scone, St Andrews diocese. Mandate to collate John Bel, priest of St Andrews diocese, to the parish church of Culasse, same diocese, vacant because Simon de Creffe, after having peaceful possession for more than a year, neglected to be ordained priest within the prescribed limit of time.
Avignon, 2 Non. Oct., anno 8; expedited, 2 Non. Jun., anno 12 [4 June, 1390]

Commentary

The three extracts from Pope Clement's letters clearly refer to the same Simon, in spite of the spelling variations. He leaves us with a curious dilemma through the use of both our candidates for an earlier version of the surname Cree. These are de Crech and de Creych on the one hand, and de Creffe on the other. It does not help us decide whether Cree might derive from the village of Creich (Fife) or the town of Crieff (Perthshire) although it adds some support to the idea that it was one or the other.

This is because Simon de Crech is associated with places close to Perth itself. In 1378 he was rector of the parish church of Collace about 7 miles north-east of Perth and held the the perpetual chaplaincy of the chapel of Forgandenny, even closer, about four miles south of Perth. At that time Simon was in line to become a a canon of Dunkeld diocese, provided he gave up the parish of Collace. Six years later, however, we see that Simon is still in St Andrews diocese. In 1386 we find that he is in fact still at Collace, and is about to lose that parish to John Bell, because he, Simon, had failed to become ordained as a priest. For some reason this third letter was not actually sent (expedita) until 1390, nearly four years after it was written, an occurrence which Burns reports to be not uncommon although normally letters were expedited within days of being written, or weeks at the most. Perhaps Simon de Crech managed to retain his "peaceful possession" of Collace for a while longer!

We are left with the knowledge that a Simon de Crech (or possibly de Creffe) held the degree of Master of Arts, was rector of Collace near Perth for the period 1378 to 1390 and also held a perpetual chaplaincy of the chapel of Forgandenny, also near Perth.