Complex sentence: During his lifetime Lorenzo Lotto was a well respected painter and certainly popular in Northern Italy; he is traditionally included in the Venetian School, but his independent career actually places him outside the Venetian art scene.
Split into simpler sentences: During his lifetime, Lorenzo Lotto was a well-respected painter and certainly popular in Northern Italy. He is traditionally included in the Venetian School, but his independent career actually places him outside the Venetian art scene.