In opening the _Natural Questions_ Adelard states that Henry I was reigning when he returned to England recently. This statement, in Professor Haskins’ opinion, “would seem to imply that he originally left England for his studies in France before Henry’s accession.” I am not quite sure that this inference follows, but if it does, may one not go a step further and argue that Henry I had come to the throne since Adelard parted from his nephew at Laon to investigate the learning of the Arabs? Had Henry become king of England while Adelard was still studying or teaching in northern Gaul, he would almost certainly have heard of it, and it would have been no news to him on his return from his studies among the Arabs. If we accept this view, Adelard’s return to England would be not later than 1107. But it could scarcely be earlier, if he wrote and dedicated the _Natural Questions_ promptly after his arrival, of which he speaks as a recent event in that work, since the dedicatee did not become Bishop of Bayeux until 1107. And if the _De eodem et diverso_ was written more than seven years before the _Natural Questions_, we should have to date it back into the eleventh century, which would perhaps be too early for its dedication to William, bishop of Syracuse. And to put these two works so early is to leave a gap between them and the other known dates of Adelard’s career, 1126, 1130, and 1142-1146, and make the period of his literary productivity quite a long one. He would have been quite a graybeard when he wrote on the astrolabe for the juvenile Henry Plantagenet. On the whole, therefore, I am inclined to think that Henry I had been reigning for some time when Adelard wrote the _Natural Questions_. FOOTNOTES: [104] Haskins (1911) pp. 492-3. [105] It is true that after 1109, “The queen herself, who had for a time accompanied the movements of her husband, now resided mostly at Westminster” (G. B. Adams in Hunt and Poole, _Political History of England_, II, 151), so that Adelard would not have had many opportunities to play before her in the English possessions across the channel after that date. [106] _De eodem et diverso_, pp. 25-6, Philosophy addresses Adelard, “... cum praeterito anno in eadem musica Gallicis studiis totus sudares adessetque in serotino tempore magister artis una cum discipulis cum eorum reginaeque rogatu citharam tangeres.” [107] P. 3, line 16, “Quoniam autem in epistola hac ...”; line 25, “Hanc autem epistolam ‘De eodem et diverso’ intitulavi”; p. 34, line 7, “Vale; et utrum recte disputaverim, tecum dijudica.” [108] P. 3, line 9, “Nam et ego, cum idem metuens iniustae cuidam nepotis mei accusationi rescribere vererer, in hanc demum sententiam animum compuli, ut reprehensionis metum patienter ferrem, accusationi iniustae pro posse meo responderem.”