Over fifty years ago, Louise Imogen Guiney wrote: ‘Someone, firstin the field, should write a little book, which should be a scientific andauthentic study of Dr John Donne as a Catholic’. As Guiney pointed out, Donne’s Catholicism, even when he had ceased to practice it actively, and even after he became an Anglican minister, was a continuous influence on his life and writings. However, Donne’s biographers, those before and those since Guiney, have paid scant attention to Donne’s Catholicism, tending rather to see his life as a paradoxical development fromlibertine scepticism to Protestant fideism. Between these extremes, Donne’s religious development has usually been described in terms of riddles and contradictions, with no more than passing reference to its relativelyclear involvement in the spiritual conflict through which Catholicism was repressed in Tudor and Stuart English society. The most influential proponent of this paradoxical interpretation has undoubtedly been Izaak Walton, Donne’s friend, who inexplicably likened Donne’s rather protracted Anglican conversion to the comparatively spontaneous conversion of St Augustine. Augustus Jessopp later repeated Walton’s fundamental idea, that Donne had clean rejected Catholicism at about twenty, even though Jessopp observed that Donne was suspected by his father-in-law of Catholic sympathies as late as 1602. Edmund Gosse was the first of Donne’s biographers to acknowledge the weight of evidence illustrating Donne’s persistent Catholic sympathies; Gosse nevertheless concluded that Donne’s Catholicism had been easily corrupted in the worldly atmosphere of London in the 1590’s, that he had grown sceptical of religion altogether,and that he lapsed thereafter only occasionally into fits of Catholic religion. Very little evidence of this supposed libertine scepticism can be found. Donne was far from sharing the extraordinary sceptical atheism rumoured of Raleigh or Marlowe, and the theory that he even leaned in this directionhas little support other than weak inference from the cynical tone of some of his writings. On the contrary, Donne seems to have shared the common assumption of his time, and the main lesson of his Catholic education, that there is one true religion. But his biographers have persistently seen him (mechanically mentioning his Catholic background) as a profane writer of ‘conceited verses’ converted by saving grace into an Anglican preacher.