1) Bias: Procopius was a Byzantine historian who lived during the reign of Emperor Justinian I. He was a fervent supporter of Justinian and his policies, and his writings often reflect this bias. In his earlier works, Procopius often praised Justinian and his achievements, while in his later works, he became increasingly critical of the emperor and his government. This change in perspective may be due to Procopius's growing disillusionment with Justinian's reign, or it may simply reflect the changing political climate of the time.
2) Different Sources: Procopius may have relied on different sources for his different accounts of the same person. For example, he may have used official government records for his earlier works and more private or informal sources for his later works. This could lead to different interpretations of the same events or people.
3) Change of Perspective: Procopius may have simply changed his mind about the person in question. As a historian, he would have had access to new information and evidence over time, and this may have led him to revise his opinions. For example, Procopius may have initially been impressed by Justinian's military successes, but later came to see the negative impact of these wars on the Byzantine Empire.
4) Literary Conventions: Procopius was writing during a time when it was common for historians to use rhetoric and literary devices to make their works more engaging and persuasive. This may have led him to exaggerate certain aspects of his accounts or to present different perspectives in order to create a more dramatic or compelling narrative.