Lorenzo Trenta, a wealthy merchant from Lucca, contracted Jacopo in 1412 to design his family chapel in San Frediano, Lucca. Work on the Trenta Chapel continued concurrently with the Fonte Gaia over the next decade.
Jacopo's first work in the Trenta Chapel consisted of an intricately carved marble altar dedicated to the patron saints of the chapel: Richard, Jerome and Ursula. This is basically a conservative sacra conversazione with the Virgin and Child enthroned against a cloth of honour in a shallow central niche. To the viewer's left and right, standing in self-contained niches framed by pilasters, are Sts Ursula and Lawrence and Sts Jerome and Richard. All the niches are surmounted by steeply pitched gables. At the base is an elaborate historiated predella with scenes from the Lives of the Saints enframing a central Lamentation.