High Tower is the name of the very first Mage Tower. The name was also given to numerous other throughout the Mage Wars. Because High Tower was the first installation to use Tower Magic, its construction is a start-date for the Mage Wars. This is generally accepted on or around 3700 B.G.A..
Because the name of 'High Tower' was adopted by many towers throughout the Mage Wars, it is nearly impossible to determine the exact location or date of the original; but a specific series of towers named sequentially over the course of the First Chaotic Period, are all believed to be built by the descendants of the first High Tower.
Tradition holds that High Tower was built where two of the Three Baras meet, a strategic point of great significance. Archeological evidence at those locations fails to provide any support for this, but the changing shape of the lake over the eons could mean the current site of High Tower is underwater.
A more likely location is along the Thenius River. The "Thenius Corridor" contains hundreds of Tells and other archeological sites, most of which have not been positively identified. Asysias may be one of them.
A less widely-accepted theory states that High Tower was nowhere near Asysias, but hundreds of miles away, with a new city-state around it. The location chosen would have been more tactically advantagous, allowing the tower to command the entire region. The ruins of a tower found at the highest peak of the Anea Mountains are held by some to be High Tower. Proponents of this theory point to Anea's proximity to Lake Bara, one of the more respected proposed locations.
Opponents of the Anea Mountains location point to archeological evidence on the site which indicates origin in the late First Chaotic or mid Dynastic Periods, with the last inhabitants as late as the Second Chaotic. Proponents claim that the tower was demolished and rebuilt numerous times, leading to its current state.