Ruskin 's visits to Florence included those made in 1840, 1841, 1845, 1846, 1870, 1872, 1874 and 1882. He studied the city's art and architecture including the work of Fra Angelico and Giotto. These studies contributed to Ariadne Florentina (1873-76), 'The school of Florence', the last lecture in Aratra Penteleci (1872), The Aesthetic and Mathematic Schools of Art in Florence (1874), Val d' Arno (1874) and the guide, Mornings in Florence (1875-77). This describes Sta. Croce, the Certosa di Val d'Ema, Sta. Maria Novella, the Uffizi, the cathedral (see the Duomo), the Spanish Chapel of Sta. Maria Novella, and the Campanile, called by Ruskin 'Giotto's Tower' or 'The Shepherd's Tower'.