Castellani is among the most celebrated of 19th-century jewelers. Many travelers on the Grand Tour stopped in Rome at the Castellani family shop, located across from the famous Trevi Fountain. One of their specialties was micromosaic adornments. Although other Italian ateliers worked in this medium, none rivaled the Castellani firm in intricacy, design, and craftsmanship. Known for their participation in excavations outside Rome, the father and sons were deeply skilled in creating jewelry inspired by the work of ancient Etruscan goldsmiths.

This brooch features a circular micromosaic panel depicting the head of a lion set within a gold frame flanked by two tied batons decorated with twisted gold wire. Coinciding with a wave of nationalism, jewelers sought to evoke the glorious past in ornaments that expressed artistic, as well as political, meanings. The Castellani firm was ardent in its support of Italian unification. The imagery for this brooch may have been inspired by lions depicted on Roman floor mosaics that had been recently discovered in Pompeii.