Why did Pope Boniface VIII become involved in Florentine politics?

Pope Boniface VIII became involved in Florentine politics primarily to secure papal influence and support within the volatile landscape of the Guelfs and Ghibellines. During the late 13th and early 14th centuries, Florence was deeply divided between the "Black" Guelfs, who were wealthy merchants favoring aggressive expansion, and the "White" Guelfs, who sought to preserve peace.12

Boniface VIII aligned himself with the Black Guelfs to consolidate power and ensure the city remained a reliable ally of the papacy. This political maneuvering involved a strategic alliance with Charles of Valois, the brother of King Philip IV of France. By facilitating Charles’s entry into Florence, the Pope helped the Black Guelfs regain control, which led to the violent suppression of their rivals and the exile of prominent White Guelfs, including the poet Dante Alighieri.1

Ultimately, Boniface’s intervention was part of his broader, assertive efforts to maintain the primacy of the Roman Catholic Church over temporal powers, a stance he famously formalized in his papal bull Unam sanctam.3