Which poet is known for the sonnet form and romantic themes in the "Canzoniere"?

The "Canzoniere," also known as "Rime Sparse," is a collection of poems written by Francesco Petrarch, who is widely regarded as the master of the Italian sonnet form. His work in this collection explores themes of love, beauty, and nature, often reflecting the intense emotional experiences associated with romantic love. Petrarch's innovation with the sonnet structure, notably in the way he expressed personal emotion and longing, has had a lasting influence on poetry, especially within the Romantic movement.

In the context of the other poets mentioned, while Wordsworth, Keats, and Byron also engaged with romantic themes in their work, they are more closely associated with the English Romantic tradition and did not develop the sonnet form in the same foundational way as Petrarch did. Thus, Petrarch's contributions to the sonnet and his thematic focus on love make him the clear choice for this question.