Ascending the steep paved lane between S. Gregorio and the Parco, the picturesque church on the left with the arcaded apse and tall campanile (_c._ A.D. 1206), inlaid with coloured tiles and marbles, is that of _SS. Giovanni e Paolo_, two officers in the household of the Christian princess Constantia, daughter of the Emperor Constantine, in whose time they occupied a position of great influence and trust. When Julian the Apostate came to the throne, he attempted to persuade them to sacrifice to idols, but they refused, saying, "Our lives are at the disposal of the emperor, but our souls and our faith belong to our God." Then Julian, fearing to bring them to public martyrdom, lest their popularity should cause a rebellion and the example of their well-known fortitude be an encouragement to others, sent off soldiers to behead them privately in their own house. Hence the inscription on the spot, "Locus martyrii SS. Joannis et Paoli in ædibus propriis." The church was built by Pammachus, the friend of St. Jerome, on the site of the house of the saints. It is entered by a portico adorned with eight ancient granite columns, interesting as having been erected by the English pope, Nicholas Breakspear, A.D. 1158. The interior, in the basilica form, has sixteen ancient columns and a beautiful Opus-Alexandrinum pavement. In the centre of the floor is a stone, railed off, upon which it is said that the saints were beheaded. Their bodies are contained in a porphyry urn under the high altar. In early times these were the only bodies of saints preserved within the walls of Rome (the rest being in the catacombs). In the Sacramentary of St. Leo, in the Preface of SS. John and Paul, it is said, "Of Thy merciful providence Thou hast vouchsafed to crown not only the circuit of the city with the glorious passions of the martyrs, but also to hide in the very heart of the city itself the victorious limbs of St. John and St. Paul."[164] Above the tribune are frescoes by _Pomerancio_. A splendid chapel on the right was built 1868;--two of its alabaster pillars were the gift of Pius IX. Beneath the altar on the left of the tribune is preserved the embalmed body of St. Paul of the Cross (who died 1776), founder of the Order of Passionists, who inhabit the adjoining convent. The aged face bears a beautiful expression of repose;--the body is dressed in the robe which clothed it when living.[165]