Two times a year, in February and September, Fashion Month unfolds as a global style circuit, beginning in New York and moving through London, Milan and Paris. During the weeks of travel, industry professionals from magazine editors and writers to retail buyers and executives gather to watch designers present the collections that will define the year ahead. It’s a time when the industry gathers to take the pulse of fashion: what’s new, what’s next and who is shaping the conversation. However, this season was unusual with an extra air of anticipation. Across the four fashion capitals, fifteen creative directors presented their debut collections, marking a generational shift at some of the world’s most storied fashion houses and emerging labels alike. From bold reimaginings of legacy codes to quieter statements of intent, these debuts reflected the diverse directions in which fashion is evolving. In particular, five shows captured the tension between legacy and reinvention.At French fashion house Balenciaga, Italian designer Pierpaolo Piccioli’s debut on Sept. 23 marked a striking collision between his romantic sensibility and the house’s architectural austerity. Mr. Piccioli's vision for Balenciaga centered on grace with sculptural coats softened at the edges, draped silks that moved like shadows and tailoring reimagined with an almost ecclesiastical purity. The palette, restrained yet luminous, underscored a quiet return to emotion.At Italian fashion label Versace, Italian fashion designer Dario Vitale hinted at his new direction with the launch of a curated art project entitled “Versace Embodied.” The creative director curated an assortment of artworks from the past and present to herald his artistic vision, one in which house values such as “uncompromising strength, rigor and sexuality” were prominent. On show day, Sept. 26, Mr. Vitale paid homage to these values with a bold collection of colorful separates. As the first creative director to succeed Donatella Versace, Mr. Vitale looked to the unapologetic sensuality of founder Gianni Versace’s late-1980s designs and distilled its essence for modern sensibilities. His debut was a sharp study in power and intimacy: sculpted denim, glossy leather and backless gowns that moved with purpose rather than provocation.At Italian fashion house Bottega Veneta, English fashion designer Louise Trotter’s first outing on Sept. 28 reaffirmed the house’s reputation for tactility and understatement. Her collection wove together the brand’s signature Intrecciato leather craft with a new kind of softness: trenches molded from supple hides, airy silks draped like knitwear and tailoring that blurred the line between structure and fluidity.Perhaps the most anticipated debut came at French fashion house Dior on Oct. 1, where Irish designer Jonathan Anderson assumed one of fashion’s most scrutinized roles. Known for his conceptual clarity at Spanish fashion brand Loewe, Mr. Anderson approached Dior as an archeological dig, excavating codes, deconstructing the Bar jacket and layering romance with irony. His Dior woman was cerebral and sensual, her wardrobe alternating between sculpted couture and subversive street-inflected tailoring.Meanwhile, French designer Matthieu Blazy’s debut at French fashion house Chanel on Oct. 6 was all about restraint and reflection. Titled “Le Paradoxe,” his show unfolded like a meditation on the contradictions of Chanel itself: tradition versus transformation, daywear versus desire. There was tweed, of course, but softer; looser cuts and pearls worn without ceremony. The show concluded with an impromptu, joyous moment of celebration from Canadian model Awar Odhiang, who wore a structured white top with a voluminous, feathered skirt.