Final answer:
The radical figure in question who moved to Italy and collaborated with William Godwin is Lord Byron. He was a leading voice in political and poetic radicalism during the Romantic era.
Step-by-step explanation:
The individual who, despite a conservative upbringing, emerged as a radical in politics, thought, and poetry, and who eventually moved to Italy to collaborate with William Godwin, is B. Lord Byron. Known for his flamboyant lifestyle and controversial writings, Lord Byron became a quintessential figure of the Romantic movement.
His works often criticized the social and political issues of his time, reflecting his rebellious nature and his eventual self-imposed exile. While William Wordsworth, Samuel Taylor Coleridge, and John Keats were also significant poets of the Romantic era, it was Byron who was the most entwined with radical politics and ideas that aligned with Godwin's.