That Robert Browning and Elizabeth Barrett Browning had an influence on each other's poetry is difficult to doubt but more difficult to prove; their similar backgrounds and shared experiences, and a reticence in both to discuss their working habits, generally make attempts to fix possible influences between them problematic at best. Two periods of their shared lives, however, do provide an unusually clear record of the way each affected and was affected by the other's writings: the first, from their introduction in January 1845 until their marriage in September 1846, during which time Browning completed the last two numbers of his Bells and Pomegranates series and Elizabeth Barrett wrote her Sonnets from the Portuguese, and the second in 1855, when Browning published Men and Women. Their courtship letters show that they considered themselves engaged in a unique poetic as well as personal partnership, and their poetry of this time, together with Browning's 1855 volume, reveals that their creative interaction was more extensive than even they realized. Of particular note is the way that Browning's first version of “Saul” helped to shape the theme and imagery of Sonnets from the Portuguese, which in turn influenced his later conclusion to “Saul.”