The lack of the printing press in the setting already indicates that the designers are well aware of the divisions of knowledge shared both through time and places. Ancient Greek already knew that the Earth is a sphere and such knowledge must have been shared by those who had access to such materials even during Medieval periods. Also, despite what Bacon wrote below, printing, gunpower and the magnet all originated from China (except Chinese printing press being wooden).http://en.wikisource.org/wiki/Novum_Organum/Book_I_(Spedding)
Again, it is well to observe the force and virtue and consequences of discoveries; and these are to be seen nowhere more conspicuously than in those three which were unknown to the ancients, and of which the origin, though recent, is obscure and inglorious; namely, printing, gunpowder, and the magnet. For these three have changed the whole face and state of things throughout the world; the first in literature, the second in warfare, the third in navigation; whence have followed innumerable changes; insomuch that no empire, no sect, no star seems to have exerted greater power and influence in human affairs than these mechanical discoveries.
The knowledge about the origins of technologies is not needed to employ the technologies in question. Some knowledge can be hidden by intentional propagandas, misunderstanding, and/or unconscious biases.*
In any case, what the designers appear to be doing is how these historical factors are fitted to their setting in a convincing manner.
*After all, how could we establish knowledge without any bias? Again, ancient Greek divided knowledge systems into metaphysics and physics. In a way, the epistemology was repeated in the Western Renaissance-Modern era in the shape of Continental Rationalism and Anglo-Scottish Empiricism. Predating this, Aquinas and Ockham can be said to have played a role of bringing back knowledge of ancient Greece to human use during the shift from scholasticism to modern philosophies. Releasing knowledge occupied by religious organizations marked these periods.