 Papal claims were opposed by secular rulers, by clerical writers who saw some interest in defending the secular rulers, and by theologians unconvinced by the pro-papal arguments and concerned about the likely effects of papal encroachment. Most of the political writers of the thirteenth and fourteenth centuries were involved in controversy about the extent and limits (or absence of limits) of papal authority (Miethke 2000a; Oakley 2012: 173ff. and 2015: 14ff.).