What year was the Gallier House built?

The Gallier House, a prominent example of mid-19th-century architecture in New Orleans, was built in 1857. This house reflects the Italianate style that was popular during that era and serves as a representation of the wealth and sophistication found in New Orleans at the time. Its construction coincided with a period of economic growth and cultural flourishing in the city, making it an important landmark. Furthermore, the Gallier House was the residence of prominent architect James Gallier Jr., who played a significant role in shaping the architectural landscape of New Orleans, further enhancing the historical significance of this building.

While the other dates pertain to other notable events or structures in New Orleans' history, they do not relate to the Gallier House specifically, which is why they are not the correct answer.