Final answer:
William Cullen Bryant started writing poetry at a young age, gaining recognition for his contemplative and romantic style.
Step-by-step explanation:
William Cullen Bryant started writing poetry at a young age. He was known for his contemplative and romantic style. He gained recognition for his poem titled "Thanatopsis", which was published in 1817 when he was just 17 years old. This marked the beginning of his career as a poet.