There is always more to say, but, certainly, while Said is often read by historians, and while his work has had a considerable impact on the way historians in his area (and more broadly) think, he was by training a professor of literature, and his postcolonial theory draws heavily on advances in that field to make his points.

You might like to check out a couple of earlier responses on this topic while you wait for fresh answers to your query:

Monday Methods: Who we are is defined by who we aren't – Edward Said and Orientalism, with u/commiespaceinvader

What is the reception of the book "Orientalism" by Edward Said?, with u/Khowaga