5 Profoundly saddened by the misfortunes which the Church was then passing through, Francis conceived the incredible design of renewing everything conformably to the principles of the Christian law. After having founded a double religious family, one of Brothers, the other of Sisters, who pledged themselves by solemn vows to imitate the humility of the Cross, Francis, in the impossibility of opening the cloister to all whom the desire of being formed in his school drew to him, resolved to procure, even for souls living in the whirlpool of the world, the means to tend to Christian perfection. He founded, then, an Order properly called Tertiaries, differing from the two other Orders in that it would not bear the bond of the religious vows, but would be characterized by the same simplicity of life and the same spirit of penance. Thus the project which no founder of a regular Order had yet imagined, to cause the religious life to be practised by all, Francis first conceived the idea of and the grace of God gave him to realize it with the greatest success. We have no other proof of it than this beautiful homage of Thomas de Celano: "Marvelous workman, whose example, direction, and teachings have this admirable result, to renew in both sexes the Church of Christ and to lead to triumph a triple phalanx of souls preoccupied with their salvation." (I Cel . xv. 40).
Source: Sacra Propediem (Vatican.va)