Step 1: Concept Overview:
The question requires identifying the poet who authored a renowned definition of poetry central to the Romantic movement.
Step 2: Detailed Analysis:
The definition—"the spontaneous overflow of powerful feelings: it takes its origin from emotion recollected in tranquillity"—is a celebrated statement in English literary criticism. William Wordsworth penned this in his "Preface to Lyrical Ballads" (1800/1802 edition). [17, 19, 23, 25, 31] This preface acted as a manifesto for the Romantic poetry movement, highlighting personal emotion, experience, and everyday language, contrasting with the formal styles of the 18th century.
Step 3: Conclusion:
William Wordsworth is credited with this philosophy, thus option (1) is correct.