But he usually signed his works, and there is no signature by him in the bell tower.
Few paintings are certainly by his hand, since he did not sign his works.
He appears to have been the first professional mapmaker to sign and date his works regularly.
"It only became obligatory for Parisian masters to sign their works after 1755," he said.
Different from the traditional masters of the past, they work individually and sign their works.
Zulueta would not be allowed to sign his works until Franco died because of this.
Few artists during this early period signed their works, making attributions today difficult.
"Other artists sign their works with their name symbols, but I use this."
He would sometimes sign his works using the Latin alphabet.
Sometimes he signed his works with the pen name Erasmo.