Compare and contrast the Persian and Roman empires.

The Persian Empire and the Roman Empire were two of the great empires of ancient antiquity, though it should be noted that the Roman Empire was far more long lasting (this is assuming we are strictly speaking about the Achaemenid Empire, the first and most famous of multiple Persian dynasties). Between the conquests of Cyrus (who died in 530 BCE) and the conquests of Alexander (died 323 BCE), you are only looking at a period of approximately two hundred years. Between the rise of Augustus Caesar and the sacking of Rome, you would be looking at a period of, at a minimum, over four hundred years, and you can stretch that timeline even further if you include the history of the Roman Republic. For example, if you began the timeline with the end of the Second Punic War, you would be adding almost another two hundred years.

Both civilizations were known as tremendous road builders, using road networks for the purposes of transportation and internal communications. That being said, it is also worth noting that the Romans also were able to use the Mediterranean Sea as a critical point of internal communications that tied the empire together. (The Persians could not take advantage of the Mediterranean to the same extent, given it was so far flung inland.)

In addition, religiously speaking, it is worth noting that both the Romans and the Persians at one point subscribed to monotheistic religions. While, for much of Roman history, Rome was a polytheistic culture, the empire was converted by Christianity, which eventually became the empire's state religion. Meanwhile, the Persian Empire was associated with Zoroastrianism.

On the other hand, Rome was actually much more geographically centralized as a political power. For much of its history, political power and influence was centered around a single dominant city, Rome, though power was later, during its decline years, bifurcated between Rome and Constantinople. The Persian Empire, on the other hand, actually had multiple capitals, with the Achaemenid court migrating between them. The Roman Empire had no equivalence to that particular power structure.

What are the major similarities between the Persian and Roman empires?

At their fullest extent, the Persian Achaemenid Empire (500 B.C.) and the Roman Empire (117 A.D.) each covered approximately two million square miles.

Both empires are known for their developed road systems. Roads allowed for the movement of commodities, officials, and armies. Advanced infrastructure was crucial to the integrity of these immense empires. Roads helped create a common economic space and communication between different parts of the empire. The Persian Royal Road stretched nearly 1,700 miles from the capital of Susa, at the foot of the Zagros Mountains, to the Aegean Sea. The Royal Road had road markers, inns, and armed posts at regular intervals. At its height, the Roman Empire had approximately 250,000 miles of roadways.

If you superimpose on a map the Roman Empire on the Persian Empire at their highest extent, you will see that they held some of the same territories, including Thrace, the Anatolian Peninsula and parts of northern Africa and the Near East. They might both be considered parts of what some historians call the "Greater West." Both had contacts with and invaded Greece, with varying results. After the decline of the Roman Empire in the West, the East Roman or Byzantine Empire frequently clashed with the new Sasanian Persian Empire.

One could add many other similarities, such as impressive architecture, large formidable armies, the establishment of provinces and provincial administration, the multi-ethnic and multi-religious composition of the states despite sporadic attempts to establish religious uniformity, the lofty position of the rulers and some similarities in the notions of kingship.

Any of these themes can be productively explored and developed in an essay.

There are many similiarities between the ancient Persian empire and that of the ancient Romans.  First, both empires grew up in the same general area; that being around the Mediterranean Sea.  They both had dealing with many of the same cultures: Greeks, Egyptians, etc. They both conquered through the use of a massive military force... the largest anyone had seen for their respective time periods.  Both had very structured command centers for their military.  Both empires conquered the "known world" in their time (relative term; but speaks to their effective military prowness).