These are the legendary weapons used by the god of Time himself, Akatosh, also called Auri-El by the elves, during the Wars of the First World. The shield is considered to have several magical abilities that help to make its wielder nigh invulnerable. Its known enchantments include resistance to fire, shielding from either magical or physical attacks, healing properties, magical armor enhancement, and spell reflection. The bow can manipulate the sun in various ways. It was involved in a prophecy recorded in the Elder Scrolls, which foretold that the bow would be used to block out the sun. This has lead many to theorize a connection to the Second Impact, but it has been impossible to test such theories since the weapon is considered to be in Skyrim in the current Era.
Bow and Shield of Auri-El
'The bow was said to be carried by Auri-El himself into battle against the forces of Lorkhan in ancient and mythic times. Its craftsmanship has no equal anywhere within Tamriel and possibly beyond.'- Knight-Paladin Gelebor