Ottomans had to prove that there was no other country of origin other than Egypt and they had blood ties with Egypt.
Step-by-step explanation:
When there was a denial on the fact that the Ottomans were not Egyptians, they had to prove that they were tru Egyptians and did not have any other blood ties.
For this, the Ottomans had to show the evidence that these people had no other home or place of orgin other than Egypt. More over they had to proof that there was blood ties between Egypt and the Ottomans.