Hello,
Is it is this quest (or head or cape) ? :
http://en.allodswiki.ru/quest/1231832921
Then you have a sort of "buff" under your portrait. You need to give the NPC the exact costume he's asking for (it's on the description of the buff).
Have you started this quest yet or not at all ? If not, let it go. You'll need about 20+ costumes to end it, and unless there is a commemoration event, you won't be able to have them all easyly, or in a cheap manner.