Is the adjective clause in this sentence essential Egypt was conquered by Persia which was conquered by Alexander the Great?

In the sentence "Egypt was conquered by Persia, which was conquered by Alexander the great," the adjective clause "which was conquered by Alexander the Great" is non-essential. It provides additional information about Persia but is not crucial to understanding the main point of the sentence, which is that Egypt was conquered by Persia. Removing the clause would still leave a complete and coherent sentence.