Asetting of gregorian chant with one note per syllable is called:

 Pope Gregory is  associated with collecting and organizing the chants of the church. Gregorian chant is named after pope St. Gregory I, during whose papacy (590–604) chant was collected and codified.A setting of Gregorian chant with one note per syllable is called syllabic. 
There is no harmony i Gregorian chant. 

*blinks* youforgotyourname**