Thaumaturgy
From Heroes of Might and Magic: Olden Era Official Wiki
Thaumaturgy is a skill that lets the hero cast spells twice in the same round. It is exclusive to Magic Heroes.
Levels
Basic Thaumaturgy
The hero can use the Spellbook one more time per battle round, but only to cast a spell of a Magic School that hasn’t been used this round. Spells cost +100% mana for each use after the first.
Advanced Thaumaturgy
The hero can use the Spellbook one more time per battle round, but only to cast a spell of a Magic School that hasn’t been used this round. Spells cost +75% mana for each use after the first.
Antimage
Enemy spells cost +4 mana.
Thaumaturge Brilliance
+2 Spell Power and Knowledge.
Practical Incantations
Heroic Strike deals +10 Damage.
Expert Thaumaturgy
The hero can use the Spellbook one more time per battle round, but only to cast a spell of a Magic School that hasn’t been used this round. Spells cost +50% mana for each use after the first.
Ancient Scrolls
Adds all tier-1 spells to the hero’s Spellbook.
Vast Soul
+10% mana restored each morning.
Archmage
All the spells the hero has learned that belong to one of the Magic Schools gain 1 level(s).
Skill Synergies
Knowing Thaumaturgy will give the following benefits to other sub-skills: No results
Artifact Effects
Holy Sigil of Quix — 
Epic Relic
While worn, grants all unlearned Subskills of the following Skills: Arcane Magic, Scouting, Battlecraft, Thaumaturgy.Epic Relic
Holy Sigil of Quix grants all unlearned Thaumaturgy subskills, as well as those of Arcane Magic, Scouting and Battlecraft.
Might Skills
Offense
Defense
Leadership
Luck
Resistance
Tactics
Battlecraft
Siegecraft
Recruitment
Combat(Might Exclusive)Magic Skills
BattleMagic
Sorcery
SummonAvatar
Wisdom
DaylightMagic
NightshadeMagic
ArcaneMagic
PrimalMagic
Thaumaturgy(Magic Exclusive)General Skills
Faction Skills
