ART AND LETTERS.--This political transformation was profoundly felt in Italian literature. A new courtly poetry, that of the so-called “Sicilian School,” had come into being in the south, partly based on Provençal models, in the first quarter of the thirteenth century. Its poets--mainly Sicilians and Apulians, but with recruits from other parts of the peninsula--had almost given to Italy a literary language. “The Sicilian vernacular,” writes Dante in his _De Vulgari Eloquentia_, “seems to have gained for itself a renown beyond the others; for whatever Italians produce in poetry is called Sicilian, and we find that many native poets have sung weightily.” This he ascribes to the fostering influence of the imperial rule of the house of Suabia: “Those illustrious heroes, Frederick Caesar and his well-begotten son Manfred, showing their nobility and rectitude of soul, as long as fortune lasted, followed human things, disdaining the bestial; wherefore the noble in heart and endowed with graces strove to cleave to the majesty of such great princes; so that, in their time, whatever the excellent among Italians attempted first appeared at the court of these great sovereigns. And, because the royal throne was Sicily, it came about that whatever our predecessors produced in the vernacular is called Sicilian” (_V. E._ i. 12). The house of Anjou made Naples their capital, and treated Sicily as a conquered province. After Benevento the literary centre of Italy shifted from Palermo and the royal court of the south to Bologna and the republican cities of Tuscany. Guittone d’Arezzo (_Purg._ xxvi. 124-126) founded a school of Tuscan poets, extending the field of Italian lyrical poetry to political and ethical themes as well as love (which had been the sole subject of the Sicilian School). The beginnings of Italian literary prose had already appeared at Bologna, with the first vernacular models for composition of the rhetoricians, the masters of the _ars dictandi_. Here, within the next eight years, St. Thomas Aquinas published the first and second parts of the _Summa Theologica_; and the poetry of the first great singer of modern Italy, Guido Guinizelli (_Purg._ xxvi. 91-114), rose to spiritual heights undreamed of in the older schools, in his canzone on Love and true nobility: _Al cor gentil ripara sempre Amore_; “To the gentle heart doth Love ever repair.” And, in the sphere of the plastic arts, these were the years that saw the last triumphs of Niccolò Pisano, “the Father of Sculpture to Italy,” and the earliest masterpieces of Cimabue, the teacher of Giotto (_Purg._ xi. 94-96), the shepherd boy who came from the fields to free Italian painting from Byzantine fetters, and who “developed an artistic language which was the true expression of the Italian national character.” 2. _Dante’s Childhood and Adolescence_