"???? there was no rome in 750 bc" well, not exactly. The traditionally accepted date for the founding of Rome was either 753 or 751 BCE. Could you instead be thinking of the sack of Rome by the Galatian Celts in 386 BCE?
He had Greeks and Persians marry.
when he defeat the king darius 3
Alexander the great helped the Greeks take out the Persians
Alexander the Great first captured its Mediterranean ports so that it could no longer pose a naval threat. He massacred the Greek mercenaries in Persian service after the battle of the Granicus so that Greeks would no longer provide the armoured infantry the Persians needed, and he captured the Persian treasury after the battle of Issus. These measures stripprd the Persians of their underlying strengths.
Greeks
Persian infantry was unarmoured - they could not stand up to Macedonian and Greek armoured formations. The Persians first tried hiring Greek armoured infantry, but after winning the battle of Granicus, Alexander had the captured Greek mercenaries massacred as a warning for Greeks thinking of hiring themselves out to Persia. At the final battle of Gaugamela, the Persians had trained their own heavy infantry (Kardakes) but they were too raw and inexperienced to stand up to the seasoned phalanx of Alexander's army.
The Greeks had superior armor and tactics than did the Persians .
The Greeks and the Etruscans.
Alexander the Great became king of the Greek kingdom of Macedonia in 336 BCE after the death of his father. He took over as Hegemon of a united Greece when his father was assassinated. He became king of the Persians in 327 BCE.
No. The Persians put down the Ionian Revolt by the Greek cities in Asia Minor 499-493 BCE, captured Eretria in 490 BCE, and defeated the combined fleet of the Greek city-states at Artemesion in 480 BCE, then captured Athens.
He was never king of the Greeks - he called himself Hegemon = Leader. He finished his campaign to conquer the Persian Empire in 324 BCE after his retreat from India.
His father had a dream to unite the city-states. Shortly after he died so Alexander was his heir. Alexander took his father's dream and tried to unite the Greeks, the Persians, and the Macedonians. He failed