In the interior of the ruin--for such it is to-day--the only peculiarity to be noted is the use of the horseshoe arches in the arcades which separate the aisles from the nave, as well as the Arab dentated arches of the transept. It is the first case on record where, in a Christian temple of the importance of San Isidoro, Arab or pagan architectural elements were made use of in the decoration; that is to say, after the invasion, for previous examples were known, having most likely penetrated into the country by means of Byzantine workmen in the fifth and sixth centuries. (In San Juan de Baños.) [Illustration: APSE OF SAN ISIDORO, LEON] Instead of being lined with chapels the aisles are covered with mural paintings. These frescoes are of great archæological value on account of their great age and the evident Byzantine influence which characterizes them; artistically they are unimportant. The chief attraction of the building is the pantheon, a low, square chapel of six arches, supported in the centre by two gigantic pillars which are crowned by huge cylindrical capitals. Nothing more depressing or gloomy can be seen in the peninsula excepting the pantheon in the Escorial; it is doubtful which of the two is more melancholy. The pure Oriental origin (almost Indian!) of this pantheon is unmistakable and highly interesting. The fresco paintings which cover the ceiling and the massive ribs of the vaulting are equally morbid, representing hell-scenes from the Apocalypse, the massacre of the babes, etc. Only one or two of the Romanesque marble tombs which lined the walls are remaining to-day; the others were used by the French soldiers as drinking-troughs for their cavalry horses! IV ASTORGA The Asturica Augusta of the Romans was the capital of the northern provinces of Asturias and the central point of four military roads which led to Braga, Aquitania, Saragosse, and Tarragon. During the Visigothic domination, and especially under the reign of Witiza, Astorga as well as Leon, Toledo, and Tuy were the only four cities allowed to retain their walls. According to some accounts, Astorga was the seat of the earliest bishopric in the peninsula, having been consecrated in the first century by Santiago or his immediate followers; historically, however, the first known bishop was Dominiciano, who lived about 347 A. D. In the fourth and fifth centuries several heresies or false doctrines were ripe in Spain. Of one of these, _Libelatism_, Astorga was the centre; the other, _Priscilianism_, originally Galician, found many adherents in the fortress-town, more so than elsewhere, excepting only Tuy, Orense, and Palencia.