Why did Giovanni Boccaccio write mostly in Latin after completing the Decameron?

Giovanni Boccaccio’s shift toward writing primarily in Latin after the Decameron was driven by several interconnected factors rather than a single cause.1

A primary influence was his friendship with Petrarch, whom he met in 1350. Petrarch served as a mentor, guiding Boccaccio toward humanist scholarship and the recovery of classical antiquity, which prioritized Latin works over imaginative vernacular creation.1

Other contributing factors included:
* Personal Circumstances: Boccaccio experienced a decline in physical health and personal disappointments in love, which may have prompted him to move away from his earlier focus on themes of love and women.1
* Religious Scruples: He began to feel religious pressure to renounce his worldly studies. In 1362, he was even exhorted by a Carthusian monk to abandon his secular writings, leading him to briefly consider burning his own works.1
* Scholarly Focus: He dedicated his later years to encyclopedic and scholarly projects, such as De genealogia deorum gentilium and De claris mulieribus, which were better suited to the formal, humanist tradition of Latin composition.1