Chaucer had an incredibly interesting life. He was a diplomat, and travelled widely all over Europe – which people usually don’t expect from someone in the 14th century.
He was also an extraordinary innovator: he invented iambic pentameter, for example, which became the key poetic form in English. He wrote a huge variety of poetry in all kinds of genres, and was exceptionally widely read in many languages. So he brought something very new to English literature and culture.