I don't know much about mid-evil times, but I do know that one form of this metered music was and still is practice in the baptist church. When the deacons would lead those hyms, they sang from their hearts, with sincere praises. It is a moving experience when they get to moaning and groaning mixing those long and short notes ushering in the HOLY SPRIT, IF YOU HAVEN'T BEEN AT A BAPTIST DEVOTIONAL SERVICE,I RECOMEND YOU DO SOON, IT's a life changing experience to hear meter music and see the effect it has on his own.