The Qur’an contains many references to historical events, some of which were revealed before they even took place. One such example is the war between the Byzantines (Romans) and the Persians, which unfolded exactly as described in Surah Ar-Rum. This remarkable prophecy, paired with an astonishing linguistic detail, highlights the precision of the Qur’anic revelation.
The ayahs in this surah are referring to the war between Byzantine and Sassanid between 602-628 CE. In other words, the defeat of the Romans by the Persians, with the murder of Emperor Maurice by the usurper Phocus, Khosrow II.
According to historians, the land where the Romans faced defeat by the Persians took place near the Dead Sea region. The data collected and research carried out by NASA states that the Dead Sea is the lowest region on the Earth, at a staggering 414 meters below sea level.
In the English translations of the Qur'an, the word adna is translated as "nearby," but this word has another meaning which is "the lowest." In this context, both meanings are fulfilled in the Qur'an.
During this war, the Romans perished when both Damascus and Jerusalem fell under the control of the Persian empire. This area is nearby to the Dead Sea, the lowest land. Such is the linguistic miracle in the Qur'an. Ultimately, Allah knows best.
The Qur'an also entails that the Persians would be the first to defeat the Romans, and a few years later, the Romans will eventually emerge as victorious, by Allah’s will. This winning war was led by Emperor Heraclius, when he defeated Khosrow II, recaptured Jerusalem, and recovered the “True Cross” for the Church of the Holy Sepulchre.
It is worth noting that the Roman empire back then was Christian (people of the Book), therefore on the lineage of Abraham, and a precursor to Islam. Therefore, they too were believers (Mumin) as mentioned in the Qur'an. It is worth noting, they fought in the name of Allah to drive out the oppressors, therefore, it was no surprise that Allah would make them win the war. And Allah mentions it, before the two wars even took place.
On a side note, Prophet Muhammad (Peace Be Upon Him) had later sent Heraclius an invitation to accept Islam (Allah’s final seal on the religion), and Heraclius wanted to revert, but his people did not let him.