Extension III

Extension III was an alteration and metamagic spell that increased the time another spell lasted.

Effects
This spell was very similar to the less potent extension I: if cast directly after another spell requiring less magical power, extension III prolonged that spell to either one and a half or two times its original duration, depending on the affected spell's power.

Components
Extension I required verbal components only.

History
This spell was created by Netherese arcanist Zwei in −2559 DR (1300 NY) under the name Zwei's 3rd extension as his last and most powerful invention.

By the 1360s DR, it was considered uncommon in the magical community in Faerûn, and also only rarely found in Zakhara.

It fell out of use after the Year of Wild Magic, 1372 DR, when experienced spellcasters developed the talent to modify some aspects of their spells, like extending the duration.