Mature works
Giotto worked on other frescoes in Padua, some now lost, such as those that were in the Basilica of St. Anthony and the Palazzo della Ragione.
Numerous painters from northern Italy were influenced by Giotto's work in Padua, including Guariento, Giusto de' Menabuoi, Jacopo Avanzi, and Altichiero.
From 1306 from 1311 Giotto was in Assisi, where he painted the frescoes in the transept area of the Lower Church of the Basilica of St. Francis, including The Life of Christ, Franciscan Allegories and the Magdalene Chapel, drawing on stories from the Golden Legend and including the portrait of Bishop Teobaldo Pontano, who commissioned the work. Several assistants are mentioned, including Palerino di Guido. The style demonstrates developments from Giotto's work at Padua.
In 1311, Giotto returned to Florence. A document from 1313 about his furniture there shows that he had spent a period in Rome sometime beforehand. It is now thought that he produced the design for the famous Navicella mosaic for the courtyard of the Old St. Peter's Basilica in 1310, commissioned by Cardinal Giacomo or Jacopo Stefaneschi and now lost to the Renaissance church except for some fragments and a Baroque reconstruction. According to the cardinal's necrology, he also at least designed the Stefaneschi Triptych (c. 1320), a double-sided altarpiece for St. Peter's, now in the Vatican Pinacoteca. It shows St. Peter enthroned with saints on the front, and on the reverse, Christ is enthroned, framed with scenes of the martyrdom of Saints Peter and Paul. It is one of the few works by Giotto for which firm evidence of a commission exists. However, the style seems unlikely for either Giotto or his normal Florentine assistants so he may have had his design executed by an ad hoc workshop of Romans.
The cardinal also commissioned Giotto to decorate the apse of St. Peter's Basilica with a cycle of frescoes that were destroyed during the 16th-century renovation. According to Vasari, Giotto remained in Rome for six years, subsequently receiving numerous commissions in Italy, and in the Papal seat at Avignon, but some of the works are now recognized to be by other artists.
In Florence, where documents from 1314 to 1327 attest to his financial activities, Giotto painted an altarpiece, known as the Ognissanti Madonna, which is now on display in the Uffizi, where it is exhibited beside Cimabue's Santa Trinita Madonna and Duccio's Rucellai Madonna. The Ognissanti altarpiece is the only panel painting by Giotto that has been universally accepted by scholars, despite the fact that it is undocumented. It was painted for the Church of Ognissanti ("all saints") in Florence, which was built by an obscure religious order, known as the Humiliati. It is a large painting, 325 by 204 centimetres (128 in × 80 in), and scholars are divided on whether it was made for the main altar of the church, where it would have been viewed primarily by the brothers of the order, or for the choir screen, where it would have been more easily seen by a lay audience.
He also painted around the time the Dormition of the Virgin, now in the Berlin Gemäldegalerie, and the Crucifix in the Church of Ognissanti.