It appears that during the reigns of the first three Edwards, Rinn-duin became the seat of a town of some importance; and it was also the seat of a parish church and two monastic establishments, of which one was a priory for Knights Hospitallers, or for Cross-bearers, which, according to Ware, was said to have been founded in the reign of King John, and, as some writers say, by his express command. Be this, however, as it may, Philip de Angulo, or Costelloe, was a great benefactor to it in the reign of Henry III., if not actually, as it is probable, its founder. From the Annals of the Four Masters we learn that the celebrated Irish historian and topographer John More O’Dugan died, “among the monks of John the Baptist,” in this monastery in 1372. He was the hereditary antiquary of Hy Maine, or O’Kelly’s country, and author of the topographical and historical poem reciting the names of the principal tribes and districts in Meath, Ulster, and Connaught, with the names of the chiefs who presided over them at the close of the twelfth century, as well as of several other works of great value which have descended to our times. In 1305, the Prior of this abbey sued Odo, the Prior of Athlone, for the advowson of the vicarage of the church of Randowne.--_Rol. P. B. T. No. 52._ The other abbey is said to have been founded under the invocation of the Holy Trinity for Præmonstre Canons, by Clarus Mac Moylin O’Maolchonry, Archdeacon of Elphin, about the year 1215. Of all these structures, as well military as religious and domestic, there only remain at present deserted and time-worn ruins, but these ruins are of great interest, and speak most eloquently of the past. The most important feature amongst them is the castle, which occupies a rocky eminence, rising abruptly from the water on the shore of the small inlet called Safe Harbour, in which it may be presumed that the armed vessels employed upon Lough Ree found security under the walls of the fortress. This castle is well described by Mr Weld, in his excellent Survey of Roscommon, as being built nearly in the form of the letter P, the tail of the letter being short in proportion, and occupied by a spacious apartment for banqueting or assembly. In the head of the letter, next the upright stem, is placed the keep, a lofty, massive, and before the use of artillery, impregnable structure: it has a court before it to the east, which was defended along the curve by a strong wall, with banquette and parapet, and ditches of great depth, on the outer side. The line represented by the stem of the letter, stretching in a direction across the point, is in length above two hundred and forty feet, and is protected at its base by that great artificial fosse which insulated this lower portion of the peninsula and the castle as already stated, but which is now nearly dry, the level having been altered by the rubbish which has fallen into it from the ruins. Nearly in the centre of