Her time, 14th century Italy, was far worse than our own: rolling plagues (she was born during the Black Plague), people resigned to unseen death, deeply troubled and angry politics, and a church that was far more compromised than it appears today. There was little good, little hope, and little time.
Using the tools she had, which was mostly her own body in ascetic devotion, she argued for and practiced peace-seeking, compassion, and actually doing something for other people.[1] Mother Teresa didn’t get her model in Calcutta from nowhere. Catherine wrote letters to people in power. She did medical work with deeply sick people. She ministered to condemned prisoners. And it goes on.
In other words, she resolved to begin addressing her world’s problems with herself. And, in so doing, she became "a fragrant flower in the mystic body of the holy church."[2]
But hers wasn’t a bootstraps thing. She, in her weird medieval way, got her vision and hope in prayer and acted accordingly. She acted in love for Jesus and, consequently, loved what Jesus loves: the church and cast-aside kinds of people. She didn’t see her circumstances, she reinterpreted them in the light of the resurrection.[3] Not a bad idea. But this is no eighties-movie montage: she also worked very hard and suffered a great deal physically and socially.
So, yes, with Catherine of Siena, a Protestant has to wade through a great deal of difficult material. But what comes out is something very recognizable: a Christian intent on personal and social reform through personal holiness, social compassion, and political advocacy. In our own day, that is a figure our time could use more of.
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[1] Catherine appears at a time after the anchorites and before the Italian Renaissance, which would inevitably lead to greater and greater lay-leadership in the church. Also, not to be tautologous, she is woman. These two facts, put together, make her solution quite innovative. She practiced her ministry outside of the convent, though as part of a religious community. She lived at home, but in a cell. And her ascesis was such (read more-than-severe by modern standards), that she transformed her body from that of a woman to that of an icon. This allowed her to write popes and other powerful people; to do papal business; and to minister in contexts, such as prisons, where a woman may not have been as welcome. I'm sure there is a good deal of work in feminist or queer theology about this sort of thing, e.g. "the queering of her body."
[2] Quoting her description of priests working in the Italian churches.
[3] from her Dialogues, in the Treatise on Prayer (20):
"When therefore the soul has arrived at seeing, knowing, and tasting, in its full sweetness, this light, she runs, as one enamored and inflamed with love, to the table of holy desire; she does not see herself in herself, seeking her own consolation either spiritual or temporal, but, like one who has placed his all in this light and knowledge, and has destroyed his own will, she shuns no labor from whatever source it comes, but rather enduring the troubles, the insults, the temptations of the Devil, and the murmurings of men, eats at the table of the most holy Cross, the food of the honor of Me, the Eternal God, and of the salvation of souls; seeking no reward, either from Me or from creatures, because she is stripped of mercenary love, that is of love for Me based on interested motives, and is clothed in perfect light, loving Me in perfect purity, with no other regard than for the praise and glory of My Name, serving neither Me for her own delight, nor her neighbor for her own profit, but purely through love alone."