Apples continued their westward journey all the way to Northern Spain, where the regions of Asturias and Sagardoa in Basque have the perfect climate to grow them. This is called “Green Spain”.
When apples became made into cider instead of being eating is not clear, the Roman and Greek words for strong wine and cider are similar. Certainly it was not easy to make, considerable scare labour was needed to pulversise the apple and then extract the juice before fermentation could occur. With wine just treading the grapes with feet suffice! However cider was made here which the Asturians call Sidra.
Greek geographer Strabo writing at the time of the expansion of the Roman Empire describes sidra in "his journey" through Spain’s Asturia region in 60 B.C which would pre-date Julius Caesar’s discovery in the UK in 55BC. However, on further analysis it appears that Strabo the Greek was born in 64BC and, barring the possibility of him being a drunk literary toddler, it seems like any such reference in his works is second hand information he acquired from someone else at a later date. His writings on the topic were likely compiled between 7BC and 23AD and some sources believe he never visited Northern Spain at all.
However the first reliable references to apple orchards was in Colunga Asturia in AD 803 followed by several others and references to apple presses - lagare a few years later .
Cider is first documented in the year 950. The Codex Calixtinus which is a kind of guide for the pilgrims who followed the Camino de Santiago notes ...It is a leafy land, with rivers, meadows, extraordinary orchards, good fruits and clear water sources. But it is scarce in cities, towns and labour lands, as well as in bread, wheat and wine. In the other hand, it’s abundant in rye bread and cider, well supplied in cattle and horses, in milk and honey, and in big and small fish ". The newly established Camina de Santiago then connected Northern Spain to France and pilgrims dispersed apples and cider to France and especially Normandy where the climate was marginal for wine. The first references here was in 1082.