Priestly hiring competitions in the Catholic Church

In the Archives of the Archbishopric of Durango (Mexico) there are a number of documents about _concursos de curatos_, or priestly concourses, which were used for hiring into vacant parishes and cathedral positions. I read a blog post about another _concurso_ that required two days of analyzing Church documents in Latin, translating and commenting on them in Spanish. It looks like a formalized, competititive hiring process. When did these competitions run? Who chose the winners?