[Soyweiser]

Also, you get additional fatigue. You get the spellcasting encumbrance added tot the specific spell fatigue. (the spellcasting encumbrance is visible if you click on the encumbrance line in the specific units unit window).

Iirc swamps and hot and cold provinces add some encumbrance. (if you do not have immunity).

Also, 100- fatigue spells still require one gem.

Each additional level you have above the spell requirements reduces the fatigue by 1/X+1 with X being the amount of levels you have above the requirements.

Secondary spell levels do not help reduce fatigue in any way.

So casting a f2 spell which does 200 fatigue with a f4 mage reduces the fatigue by 1/3. For a total of (200 * 1/3 = 67 rounded up) 57 fatigue + spell casting encumbrance.

This works for all spells, no need to add the - signs to spellcasting fatigue levels. (So write, a fatigue 10 spell, not a fatigue 10- spell).