Milan and the rest of the fashion world stepped off the ready-to-wear hamster wheel this week to pay tribute to Franca Sozzani, the longtime editor of Italian Vogue, who died in December at 66.

The winter sky was slate gray on Monday afternoon as the great and the good of the industry gathered in the Duomo, the city’s massive Gothic cathedral, for a service in Ms. Sozzani’s memory. Crowds thronged behind safety barriers outside as hundreds of mourners filed in.