SUMMARY: The « accommodata renovatio » of the Institutes of Consecrated Life, desired and promoted by Ecumenical Vatican Council II, has truly represented for them a moment of great hope, of a return to the genuine sources of the charism, of commitment on all levels and in all se­ctors for an authentic renewal of life and apostolates; but it has been also an occasion of anxiety and uncertainty on what to achieve, as often happens in the presence of novelties. In particular, the Order of Friars Minor had encountered the Council after a long and difficult history of reforms and with certain problems - which had their roots at the very heart of their identity - not yet re­solved to the satisfaction of all after centuries of heated and, at times, controversial debates. Among these, in the first place, the obligatoriness « sub gravi » of the Franciscan Rule disturbed the conscience and interrogated the intelligence of the friars. In this study the Author analyses cer­tain texts on this theme of three renowned Franciscan scholars: H. Holzapfel, K. Esser, A. Boni, putting in evidence the whole complex of conflicting opinions, of different solutions, the difficultes of method and, at times, of the individuation of the real origins of the problem, tackled often uni­laterally and on the basis of « emotional » rather than « rational » incentive, to arrive to the point of demonstrating how the theory expressed eventually (in 1967) by A. Boni is and must remain the most valid, since, being completely free of any controversial intention, directly founded on the analysis of the Sources read « secundum propriam verborum significationem in textu et conte-xtu consideratam » (can. 17) and « sounded » with love and intelligence, it arrives, with scientific rigour, at the historical and juridical solution (truth!) of the vexata quaestio.