Time travel

Time travel was th means by which an individual, a group of people, or even an entire city could travel backward through time to previous year or even, bygone era, or even an ancient civilization. It an extremely difficult and demanding feat that came with great risk to anyone involved.

Restrictions
Time travel was strictly regulated by Mystryl, the ancient goddess of time and magic. In the ages before the fall of Netheril she allowed no being to change the "stream of time" save for a single manner of her choosing, the time conduit, and was omniscient to any anomalous events that attempted to bypass her law.

Spells
The primary magical means of time travel was time conduit, an ancient chronomancy spell that opened temporary portal to another time. The caster and their allies could venture through the conduit to a time and realm with which they were at least moderately knowledgeable, under the restrictions placed forth my Mystryl. Their journey would last for the duration of one year exactly, beginning on the year's first day and ending on its last. No individual could later return to that same year, lest the anomaly be detected and they were violently shot back in time up to an entire century, hundreds of miles away.

Simply put there were no known magical means to bypass the restrictions of the time conduit.

The time conduit spell required specific knowledge of the year or era during which the destination time occurred. As such, there were no signs it could be used to travel forward in time.

Portals
The Realms were home to at least five time gates, permanent portals that allowed for time travel, and two very different portals that allowed for some limited form of time travel.

Three time gates were recorded by the ancient of scholars of Mystryl, whose studies back to the time of ancient Netheril:
 * A cave set deep within the Spine of the World mounts in the North.
 * Atop the toppled apex of Misken's Peak, frozen beneath the Great Glacier.
 * In a cave within Mount Andrus in the Vilhon Reach; current whereabouts unknown due to an erroneous transcription of the locale as "Andrio's Peak".

The fourth time gate known only ten elves of the city of Chrysalis:
 * Within a cave beneath a waterfall that fed Mirror Lake in Synnoria.

A fifth time gate reconstructed using by the Imperial Society of Historial Study:
 * Hidden inside a monastery set deep within the Orsraun Mountains in Turmish.

A constantly moving whirlpool associated with the goddess Umberlee:
 * The mysterious vortex called Umberlee's Fist was actually a traveling undersea portal that transported vessels across great distances, and due to its poor temporal anchoring, occasionally back in time.