Vasari says that Andrea Tafi was considered "an excellent, nay, a divine artist" in his specialty. Andrea, himself more modest, visited Venice, and deigned to take instruction from Greek mosaic workers, who were employed at St. Mark's. One of them, Apollonius, became attached to Tafi, and this is how he came to accompany him to Florence. The work on the Baptistery was done actually _in situ_, every cube being set directly in the plaster. The work is still extant, and the technical and constructive features are perfect, since their restoration. It is amusing to read Vasari's patronizing account of Tafi; from the late Renaissance point of view, the mosaic worker seemed to be a barbarous Goth at best: "The good fortune of Andrea was really great," says Vasari, "to be born in an age which, doing all things in the rudest manner, could value so highly the works of an artist who really merited so little, not to say nothing!" Gaddo Gaddi was a painstaking worker in mosaic, executing some works on a small scale entirely in eggshells of varying tints. In the Baroncelli chapel in Florence is a painting by Taddeo Gaddi, in which occur the portraits of his father, Gaddo Gaddi, and Andrea Tafi. About this time the delightful mosaic at St. Clemente, in Rome, was executed. With its central cross and graceful vine decorations, it stands out unique among the groups of saints and seraphs, of angels and hierarchies, of most of the Roman apsidal ornaments. The mosaic in the basilica of St. John Lateran is by Jacopo Torriti. In the design there are two inconspicuous figures, intentionally smaller than the others, of two monks on their knees, working, with measure and compass. These represent Jacopo Torriti and his co-worker, Camerino. One of them is inscribed (translated) "Jacopo Torriti, painter, did this work," and the other, "Brother Jacopo Camerino, companion of the master worker, commends himself to the blessed John." The tools and implements used by mosaic artists are represented in the hands of these two monks. Torriti was apparently a greater man in some respects than his contemporaries. He based his art rather on Roman than Greek tradition, and his works exhibit less Byzantine formality than many mosaics of the period. On the apse of Sta. Maria Maggiore there appears a signature, "Jacopo Torriti made this work in mosaic." Gaddo Gaddi also added a composition below the vault, about 1308.