This immense palace, which covered very nearly nine English acres of ground, was almost a perfect square terminating at the four corners by a quadrangular tower. Its faces were directed as nearly as possible to the four cardinal points—the southern side being pointed to the shore and facing the sea. It still exists in good preservation and forms a grand object of attraction to the visitor entering the harbour. Two streets intersected each other at right angles nearly in the centre of it, which has lately been completely excavated and is now fully exposed to view.
The following description by the late Mr. Paton (author of "Highlands and Islands of the Adriatic," one of the most charming books ever printed) will convey to the reader a far clearer impression than anything I could pen; I therefore make no apology for inserting it here, and whoever should wish to go still deeper into the matter and learn all that is to be learned concerning this palace, I refer him to Mr. Adams' book "Spalato Restored," which is a perfectly exhaustive treatise on the subject.
"At the outset we are struck with the enormous extent of the palace, which is not less than nine acres and a half; so that even Constantine Porphyrogenitus speaks of it with admiration, as one of the greatest edifices then extant. In the time of Diocletian, his great retinue and a pretorian cohort could be lodged with convenience in it. Sixteen towers gave strength and elegance to the edifice, of which the largest were those at the four corners. The back of the edifice looked to the north-east on the land-side, and there was the principal entrance, the Porta Aurea, or golden gate, which led to the Peristylium, a great court of granite columns; and the cross street which intersected the principal passage at right angles was terminated at each end by gates, the one the Porta Ferrea, or iron gate, the other the Porta Ænea, or gate of brass, which are so called to this day.
"This peristylium, or court of granite columns, was flanked by two temples; the greater of Jupiter, and the smaller of Esculapius; the former, a lofty octagon, was ascended by a stair of fifteen steps; an uneven number being generally found in the temples of the ancients, that, beginning to move with the right foot, they might, of course, place it first upon the uppermost step in order to enter the temple—a form which was accounted respectful in approaching the Deity. From the peristylium, or court of granite columns, the Roman entered the principal inhabited part of the palace; first was the porticus of Corinthian order, then the circular dome-covered vestibulum, with the Lares and Penates; then the atrium, or quadrangular hall, ninety-eight by forty-five with its arms and trophies dedicated to ancestry; and last of all the crypto-porticus, or grand gallery, looking to the south-west, thus facing the sea, and forming a noble promenade of five hundred and fifteen feet in length, in which, during the heat of Summer or inclemency of Winter, the Emperor could take exercise. This crypto-porticus was the principal feature of the palace, and the well-known taste of Diocletian leads us to suppose that the choicest statuary and paintings of the Old World must have adorned its walls. The relics of Pompeii give some idea of the classic fancy in ornament, the harmonizing contrasts in colour, and the consummate skill in tessellation employed in the domestic architecture of the ancients; and if we relieve these splendours with the latest fascination in the unpretending forms of Greek statuary, how puny is the utmost magnificence of Versailles compared with the dwelling of the retired Roman!