MILAN — Domenico Dolce and Stefano Gabbana went on a whirlwind tour of Ancient Rome in the spring collection they showed for D&G on Thursday. The theme was inspired by the new boutique the pair will open in Caesar’s Palace in Las Vegas in November, but the results would certainly have startled Calpurnia. There were leather bras over handkerchief skirts, draped blouses worn with minis and even Ts with souvenir scenes of the Colosseum. Here, a mini tunic dress meant for the naughtiest empress around. For more on the season, see pages 6 and 7.