Dorothy Wordsworth, the sister-turned-muse of her older brother, the poet William Wordsworth, refused to attend his wedding. When a guest informed her that the deal was sealed, she fainted. This exhibition, staged at William and Dorothy’s childhood home in Cockermouth, England, examines how their adolescence—spent outdoors, not far from the Irish Sea—and a seven-year separation after their mother’s death in 1778, shaped their relationship as well as their writing. One of the prized possessions displayed in the house: Dorothy’s 251-year old, hand-sewn baby bonnet. —J.D.