Context: the guy at the left is emperor maricius of the eastern roman empire and the right is Shyruye or known by his regnal name Kavad II or Ghobad II. Maricius was actually the grandfather of kavad as he was the father of one of khosrow’s wives: Maria

And it is about the Sassanid civil war of 628\~ 632 AD a conflict that broke out after the execution of the Sasanian king Khosrow II between the nobles of different factions, notably the Parthian (Pahlav) faction, the Persian (Parsig) faction, the Nimruzi faction, and the faction of general Shahrbaraz. Rapid turnover of rulers and increasing provincial landholder power further diminished the empire. Over a period of four years and fourteen successive kings, the Sasanian Empire weakened considerably, and the power of the central authority passed into the hands of its generals, contributing to its fall.

The Background : In 628, Khosrow II was overthrown by the feudal families of Iran, which included the Ispahbudhan spahbed Farrukh Hormizd and his two sons, Rostam Farrokhzad and Farrukhzad, Shahrbaraz of the Mihran family, the Armenian faction represented by Varaztirots II Bagratuni, and finally Kanadbak of the Kanārangīyān family. On 25 February, Khosrow's son Sheroe, along with his commander Aspad Gushnasp, captured Ctesiphon and imprisoned Khosrow II. He then proclaimed himself as shah of the Sasanian Empire and assumed the dynastic name of Kavad II. He proceeded to have all his brothers and half-brothers executed, including the heir Mardanshah, who was Khosrow's favourite son. The murder of all his brothers, "all well-educated, valiant, and chivalrous men",stripped the Sasanian dynasty of a future competent ruler, and has been described as a "mad rampage" and "reckless".Three days later he ordered Mihr Hormozd to execute his father. However, after the regicide of his father, Kavad also proceeded to have Mihr Hormozd killed.

Due to Kavad's actions, his reign is seen as a turning point in Sasanian history, and has been argued by some scholars as playing a key role in the fall of the Sasanian Empire. The overthrow and death of Khosrow culminated in the Sasanian civil war of 628–632, with the most powerful members of the nobility gaining full autonomy and starting to create their own government. The hostilities between the Persian (Parsig) and Parthian (Pahlav) noble families were also resumed, which split up the wealth of the nation.

Kavad also took all the properties of Farrukhzad and put him under arrest in Istakhr. During this period, Piruz Khosrow assumed the leadership of the Parsig faction, while the Ispahbudhan Farrukh Hormizd, assumed the leadership of the Pahlav faction. Kavad II later died from a devastating plague after only a few months reign on 6 September 628. He was succeeded by his eight-year-old son Ardashir III.

(Spoilers Extended) What is this thing most similar to what GRRM wrote