What is the term for a type of song that summons or memorializes spirits?

I read a word online a long time ago and I forgot it. It was just one word and it was a term used to describe a type of classical music, old italian, religious orchestral music that summons dead people or memorializes them. I remember listening to O Fortuna that day and went on a search spree. I cant remember the word for the life of me and its driving me nuts.
Asked Mar 17, 2014

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