The tower itself is essentially a hollow stone structure with a spiral staircase winding up the inside, each step of which acts as a ritual site. Each step is usually called a 'story' or 'level', though most steps are no more than a few square feet, and sometimes less than a foot below the next level. As such, a Mage Tower might be thousands of stories high, while only a few hundred feet into the air.
Tower levels can very drastically in size, though they tended to grow as the Mage Wars progressed. The largest-known towers were built by the Marcon Alliance, each step of which contained lavish accommodations, as well as private elevators (worked by slaves, with pulleys, of course: the Marcons detested high tech., and preferred to do everything by slave-labor). The individual 'steps' were around 12 feet different in height, making the internal stair useless for anything but spellcasting. Though towers capable of holding more wizards existed, in terms of sheer enormity, the Marcons built the largest.
"Command" refers to a mage tower's areas of influence, where it can reach. Towers were built tall, or even on mountain-tops, to reach large areas. Anywhere within the tower's field of vision, the mages could reach, and therefore cast spells.
High Tower used special communication stones and mathematics in order to direct spells over mountains and around obstacles. Thought highly effective, this technique was strangely never used by any other tower. Historian speculate that Nathan Searlin may have discovered mathematical knowledge not in common use in the region at the time, and this explains why his opponents had to rely entirely on line of sight. By the Dynastic Period when advanced forms of math such as algebra and trigonometry became common, the practice of using line of sight in tower magic was already deeply ingrained.
The Sigil Stone is the heart of the Mage Tower, and is required for casting more powerful spells. In smaller towers operating with only a few dozen mages, the Arch Magus acts as the focal point of the magic. In larger towers, having scores and upwards of hundreds, sometimes even thousands of mages, a single individual could not possibly hope to control that much energy.
The simplest sigil stones are simply a focus item: something to act as a kind of spillway to direct the magic. The Arch Magus, no longer required to be a conduit for the power himself, is then much more able to direct and manipulate it.
In small to mid-sized towers, it was very common for the Arch Magus to keep the sigil stone in his staff or cane, thus preventing the other mages from using the tower without him. Larger towers, requiring larger stones, would often have a permanent ritual site at the top where the stone would reside.
The material of the stone itself is not important, and indeed the word "Stone" is a misnomer, as they are typically made of metal. If a tower owned any precious Magical Materials, the stone would no doubt be made of them. The exception is silver, which, while relatively common and cheap (as compared to other magical metals), its low melting point made it a poor choice.
Obsidian was very popular, especially for towers that practiced black magic. While having a much lower melting point than silver, its hard nature was easier to contain. Obsidian also heavily amplified elemental earth magic, which is a frequent component in dark spells.
At least one tower is known to have used wooden sigil stones, providing a new stone for each casting. It is believed that the tower would employ a very strong, hard wood, that would burn off during the spell-casting, and add additional power to the spell.
Early in the Mage Wars, such as during the First Chaotic Period, Sigil Stones were almost exclusively round. Only later, during the height of the Dynastic Period did the stones begin to see unusual and exotic shapes. Many examples of surviving stones from this era defy explanation, and present-day scholars of Tower Magic can only conclude that each tower had its own secrets on the subject. One particularly notable example, the Tir-Aangriel, was used by many towers and is a very complex shape, yet is also believed to be a relic, predating the Mage Wars by tens of thousands of years.
List of Famous Towers
Lake Bentika Towers,