Constans II vs Darius III

Constans II issued the Typos, an edict that forbade discussion of the Monothelite controversy. The edict aimed to end religious strife but was condemned by the Papacy and failed to restore unity.

Constans II became the last Byzantine emperor to visit Rome. He was received by Pope Vitalian and spent twelve days in the city, stripping it of many bronze ornaments and statues to be sent to Constantinople.

While residing in Syracuse, Sicily, Constans II was assassinated in his bath by a chamberlain. His death was part of a conspiracy, and his son Constantine IV succeeded him after suppressing the usurper Mezezius.

Constans II's son, Constantine IV, was actually the emperor during the first Arab siege of Constantinople. Constans II himself faced Arab raids but did not command the defense of the capital during the major siege.

Darius III commanded the Persian army against Alexander the Great at Issus in Cilicia. Alexander's forces defeated the larger Persian army, and Darius fled the battlefield, leaving his family and baggage train to be captured.

Darius III assembled a massive army from across the empire to confront Alexander near Arbela. Alexander's tactical brilliance led to a decisive Persian defeat, and Darius again fled the field, effectively ending Achaemenid resistance.

Alexander the Great captured and sacked Persepolis, the ceremonial capital of the Achaemenid Empire. The palace complex was burned, symbolizing the end of Persian imperial power and the transfer of hegemony to Macedonia.

After Gaugamela, Darius fled eastward through Media and Parthia. He was deposed and imprisoned by his own satrap Bessus, then murdered by Bessus's followers near Hecatompylos. Alexander later gave Darius a royal burial at Persepolis.