The Church of the Holy Trinity was built in Romanesque style in the second half of the 11th century, and rebuilt between 1258 and 1280 according to a design by Nicola Pisano. Its baroque façade, however, was completed by Bernardo Buontalenti. Here you can see some capitals decorated with carved cherubs and The Holy Trinity over the main door.

Highlights of the austere interior include what is known as the Sassetti Chapel, where visitors will find a series of frescoes by Domenico Ghirlandaio depicting the life of St. Francis of Assisi. The wealthy banker Francesco Sassetti, promoter of the project, wished to create a chapel that was both on a par with his immense fortune and could rival that of its major competitor, Giovanni Tornabuoni, who had paid for the frescoes of the Basilica of Santa Maria Novella.

Of all the scenes that can be seen in the Sassetti Chapel, highlights include the mural entitled "Saint Francis receiving the Order" in which Pope Honorius III confers holy rule on the Franciscan order. This painting is especially interesting because it includes the Piazza della Signoria along with portraits of figures such as Lorenzo the Magnificent or Sassetti himself. 

Moreover, in another of the frescoes, entitled "The Miracle of the Resurrected Child" visitors can see what the church looked like before the construction of the façade by Buontalenti.

Visitors should also pay attention to the high altar, which features another altarpiece by Ghirlandaio: the beautiful "The Adoration of the Magi", which features portraits of Sassetti and his wife.