Has there been a continuous history of Persia, unified under a central government going back 2,600 years?
There are no ancient nations with uninterrupted histories. Phoenicia was invaded by the Babylonians, the Persians, the Greeks, and then by the Romans. Egypt of the Pharaohs later became a Roman province, later occupied by Arabs, and then by the Ottomans. After the fall of the Roman Empire there was no unified Italian state for centuries. In the Middle Ages Germany and Italy were provinces of the Holy Roman Empire. Italy and Germany became modern unified independent states only in 1870. Persia was an independent nation under the Hakhamaneshis, the Sassanid, the Safavid, the Qajar, the Pahlavi, and the Islamic Republic. There was no unified nation-state called Persia in the period between Sassanid and Safavid states (641-1500 CE). Persia was a part of the Arab Islamic Empire and later Seljukid Empire. At different times there were regional Persian rulers, who paid taxes to the Arab Calife of Baghdad. With the important exception of Mullah Sadra who lived under the Safavid rule, very few
