19 events the sources record for this year, grouped by region.
What happened
China (2)
Cao Cao stationed troops at Juchao and advanced to Haoxi west of the river, pressing Sun Quan at Ruxu Mouth and forcing him back. (Records of the Three Kingdoms (Sanguozhi) 魏書 武帝紀 (卷01) 建安22년)
In the first month Wei King Cao Cao was stationed at Juchao, and Sun Quan guarded Ruxu. In the second month Cao Cao attacked; in Sun Quan's camp, Zhang Xin praised Xu Sheng as loyal and upright. (Zizhi Tongjian (Comprehensive Mirror) 資治通鑑 卷068 (원문 단락 #5423, 217년))
West Asia (12)
Caracalla dies beside Edessa, on a tour of Syria, after a reign of six years. (Aurelius Victor, De Caesaribus Aur. Vict. Caes. 21.5)
On 8 April, on the road from Edessa to Carrhae, Antoninus dismounted to relieve himself and Martialis stabbed him with a dagger, after which his escort officers finished him off (Cassius Dio, Roman History 79(78).5.4)
Julia Domna, at Antioch, beat her breast on hearing of her son's death, which reactivated her breast cancer, and she died by fasting (Cassius Dio, Roman History 79(78).23.1)
Diadumenianus, passing among the soldiers at Antioch to meet his father, was proclaimed Caesar by the soldiers and also received the name Antoninus (Cassius Dio, Roman History 79(78).19)
Artabanus invaded Mesopotamia; Macrinus marched toward Nisibis and lost a battle that began over water sources, and his camp was saved by the baggage carriers (Cassius Dio, Roman History 79(78).26)
Caracalla dies near Edessa in Osrhoene while preparing a Parthian campaign and is buried with a state funeral. (Eutropius, Breviarium Eutr. 8.20)
Caracalla sets out with only a small cavalry escort to visit the temple of the Moon at Carrhae. (Herodian, History of the Empire 4.13)
Martialis stabs Caracalla from behind as he steps away alone to relieve himself, and kills him. The prefect Macrinus had arranged it. (Herodian, History of the Empire 4.13)
The army raises Macrinus to emperor (they first proposed an older man, who declined). (Herodian, History of the Empire 4.14)
Macrinus's army confronts the Parthians and scatters caltrops that injure camels and cavalry. Bodies pile up like mountains, and both sides withdraw. (Herodian, History of the Empire 4.15)
After two days' interval following Antoninus's death, on the fourth day (Severus's birthday) the soldiers in Mesopotamia acclaimed Macrinus as emperor (Cassius Dio, Roman History 79(78).11)
On the day of the Vulcanalia lightning struck the amphitheater and burned both the upper tiers and the arena, and not even draining the aqueducts put it out; the Tiber flooded the same day (Cassius Dio, Roman History 79(78).25.2)
Macrinus bought peace by giving Artabanus and his entourage 200 million sesterces in gifts and gold; he did not tell the Senate the full story and accepted victory sacrifices (Cassius Dio, Roman History 79(78).27.1)
After Caracalla's murder, the praetorian prefect Opellius Macrinus seizes imperial power and takes the name 'Severus' or 'Antoninus' (Historia Augusta Macr. 2.1)
He fights Parthia with a large army but is defeated; when Artabanus takes revenge he sues for peace, which is soon accepted (Historia Augusta Macr. 8.1, 8.3)