Science and Technology
Author George R.R. Martin has stated that the storyline in his A Song of Ice and Fire novels is partially (and loosely) inspired by the War of the Roses, the civil war that occurred in England in the late 1400s following its defeat in the Hundred Years' War. Just as the War of the Roses was fought between the Yorks and Lancasters, the conflict in Game of Thrones is between the Starks andLannisters. The technology level in their society more or less matches Late Medieval Europe, i.e. right before the use of gunpowder and cannons revolutionized medieval warfare and brought it into the Early Modern era.
Science and technology have not significantly advanced in the past several centuries. Recorded history is indeed vastly longer in the fantasy-world than in real-life: the Valyrian Freehold existed for an astonishing five thousand years before its fall. Written history in Westeros begins with the Andal Invasion six thousand years ago, albeit much of this is fragmentary and biased (see main article "Timeline"). It is possible that in earlier ages when magic was more prevalent, there was less drive to innovate new tools with science, leaving technology levels static for many centuries. Even so, while the general rule holds that gunpowder has not been discovered, there is not a one-for-one correspondence between the technology level in the real-life Middle Ages and the fantasy world of Westeros. For example, certain medical knowledge is much more advanced and accurate in Westeros than it was in the Middle Ages (partially because certain discoveries in history have been accidental, i.e. penicillin, not the culmination of a long aggregation of previous discoveries). The peoples in Westeros and beyond are also capable of producing vast feats of architecture, such as the Red Keep in King's Landing, without the use of magic at all.
Military technology in Westeros and Essos is loosely comparable to the kinds used during the real-life Hundred Years' War and War of the Roses. Crossbows are prevalent, though they have not superseded longbows, which are also quite common on the battlefield (again, much like the 1400s in real-life northwestern Europe). Various kinds of advanced siege weapons such as catapults are employed. Horse cavalry are widely used, and some regions of Essos are known to use mounted elephants. Heavy cavalry, using mounted knights in full plate armor, is a mainstay of the battlefield, though they are more commonly fielded by the wealthier regions of Westeros (i.e. the Reach or the Westerlands), while the poorer kingdoms (such as The North or the Iron Islands) make do with chain mail instead of full plate armor. Many armies frequently make use of different kinds of mercenaries.
