Of his many public works carried out at Frascati, of which it is now necessary to speak, by far the most important and useful was the founding of the Seminary that still survives intact as a lasting memorial to the zeal and bounty of Henry Cardinal Stuart, Duke of York.
On the total suppression of the Society of Jesus by Clement XIV in 1769, the Cardinal Duke, who had always shown a special interest in education, applied to the reforming Pope for a grant of the now deserted (Villa Tusclana) Jesuit college at Frascati, with the object of changing it into a seminary for his diocese, the clergy of which he had apparently found anything but cultivated or well-disciplined on the occasion of the Synod of 1763.The Pope readily gave the desired permission, and by a papal brief—adfuturam rei memoriam—dated February I2th, 1770, the buildings were handed over to the Cardinal Duke, who at once expended the large sum of 12,000 crowns in adapting them to the required purpose and in making various additions of outlying property. This newly-founded Seminary always occupied the first place in his heart, and its management continued for many years a source of loving care and anxiety to him, whilst he spared neither time, trouble, nor money in making his Seminary, from the two standpoints of learning and accommodation, a model establishment of its class. Besides carrying out many structural improvements, he also included two more buildings, one to contain a printing-press and the other a stage, on which were to be performed dramas, both classical and modern, that might appeal to the tastes and improve the minds of his pupils and their professors.
But the chief pride of the Seminary was the great Library, still existing, which was brought together with care and judgment, and arranged in a fine chamber enriched with a ceiling-painting in allegorical designs from the brush of Taddeo Cunnoz, and with a handsome pavement, in which the eminent mathematician Calandrelli had been engaged to fix a meridian.To Frascati was now removed from Rome practically the whole of the Cardinal Duke's private collection of books, manuscripts and engravings (including not a few valuable works that had formerly belonged to James II of England, to the Chevalier St. George, and to the royal Polish House of Sobieski) in order to form the nucleus of the projected library. Friends and suppliants, both great and small, who were anxious to ingratiate themselves, now began to present volumes from time to time,
so that at the date of the French invasion of the Papal States the library of the Seminary of Frascati had probably become one of the best stocked collections of its kind in Italy. Although the buildings were pillaged by the French troops at the close of the eighteenth century,and several of the choicest treasures were dispersed or destroyed, this library at Frascati still contains some objects of historical or artistic interest amongst the general mass of theological and classical literature. Two specimens at least survive
Link (here) to the book entitled, The last of the Royal Stuarts: Henry Stuart, Cardinal Duke of York By Herbert Millingchamp Vaughan