The translator Gerard of Cremona (1114-87) was her contemporary, and his labours made available for western readers a number of scientific works which had previously circulated only among Arabic-speaking peoples.[35] Several of these works, notably Ptolemy’s _Almagest_, Messahalah’s _De Orbe_, and the Aristotelian _De Caelo et Mundo_, contain material on the form of the universe and on the nature of the elements, and some of them probably reached the Rhineland in time to be used by Hildegard. The _Almagest_, however, was not translated until 1175, and was thus inaccessible to Hildegard.[36] Moreover, as she never uses an Arabic medical term, it is reasonably certain that she did not consult Gerard’s translation of Avicenna, which is crowded with Arabisms. On the other hand, the influence of the Salernitan school may be discerned in several of her scientific ideas. The _Regimen Sanitatis_ of Salerno, written about 1101, was rapidly diffused throughout Europe, and must have reached the Rhineland at least a generation before the _Liber Divinorum Operum_ was composed. This cycle of verses may well have reinforced some of her microcosmic ideas,[37] and suggested also her views on the generation of man,[38] on the effects of wind on health,[39] and on the influence of the stars.[40] On the subject of the form of the earth Hildegard expressed herself definitely as a spherist,[41] a point of view more widely accepted in the earlier Middle Ages than is perhaps generally supposed. She considers in the usual mediaeval fashion that this globe is surrounded by celestial spheres that influence terrestrial events.[42] But while she claims that human affairs, and especially human diseases, are controlled, under God, by the heavenly cosmos, she yet commits herself to none of that more detailed astrological doctrine that was developing in her time, and came to efflorescence in the following centuries. In this respect she follows the earlier and somewhat more scientific spirit of such writers as Messahalah, rather than the wilder theories of her own age. The shortness and simplicity of Messahalah’s tract on the sphere made it very popular. It was probably one of the earliest to be translated into Latin; and its contents would account for the change which, as we shall see, came over Hildegard’s scientific views in her later years. The general conception of the universe as a series of concentric elemental spheres had certainly penetrated to Western Europe centuries before Hildegard’s time. Nevertheless the prophetess presents it to her audience as a new and striking revelation. We may thus suppose that translations of Messahalah, or of whatever other work she drew upon for the purpose, did not reach the Upper Rhineland, or rather did not become accepted by the circles in which Hildegard moved, until about the decade 1141-50, during which she was occupied in the composition of her _Scivias_.