User can use magic as magic level 3 wizard (select spells as Necromancer). Each time the bearer casts a spell, roll 2D6 against his Ld. If he fails, he can do nothing until the next magic phase.
A character wearing the Crown of Sorcery has the abilities of a wizard but can still wear armour as normal - this does not inhibit the character's ability to cast spells. There is nothing to prevent a character wearing the Crown and a helmet as the one simply sits on the other.
Note that this item has a special rule designed for campaign play. In normal play this works as follows. Test at the end of each game to determine if the character is affected. If he is, then the character (together with any mount/chariot he rides) counts as slain for purposes of victory points. In addition, you may not use the magic item thereafter when you play the same opponent. The item can be reintroduced, but only if your opponent agrees.