Sentence:  An effort was made, particularly in the Latin church, to correct the disorders of popular elections without taking away the rights of the people. This they did by the agency of an <WSD>"interventor</WSD>"<!--sic italics-->, who was sent among the people to endeavour to unite their votes upon a given person ... 
Meaning of the word marked with <WSD> tags:  One who intervenes; a mediator, especially one designated by a church to reconcile parties and unite them in the choice of officers.