The next Bishop, Thomas of Hatfield, a secular clerk of good family, great military capacity (he was one of the commanders at Nevill’s Cross) and architectural taste, and tutor to the Black Prince, was stimulated by the examples of Islip (Canterbury College) and Wykeham to endow the Durham Hall permanently; his charter still exists in the form of a contract with the prior and convent, executed in 1380. Four trustees (including William Walworth Lord Mayor, and Master Uthred a monk of Durham, who was soon afterwards tried for heresy) will furnish money to purchase property worth two hundred marks a year, to maintain a warden and seven other student monks, under rules closely resembling those of a Benedictine cell, and also (which is a new departure) eight secular students in Grammar and Philosophy at five marks each, from Durham and North Yorkshire, on the nomination of the prior, who are to dine and sleep apart from the monks, and perform any _honesta ministeria_ that do not interfere with their studies. These are under no obligation to take orders or vows; but must take an oath to further the interests of the Church of Durham. No buildings are mentioned, but probably the north and east sides of the original quadrangle containing library, warden’s lodging, and rooms, had been built _c._ 1350. Hatfield died in 1381; the convent purchased from John Lord Nevill of Raby and appropriated the churches of Frampton (Linc.), Fishlake and Bossall (Yorks), and Roddington (Notts), giving for them £1080 and two other churches. The revenue was two hundred and sixty marks. Many of the bursarial rolls sent to Durham between 1399 and 1496 are preserved there. But the income soon declined; and even after the convent had added the church of Brantingham, there was generally a deficit. Little further is known: Bishops Skirlaw and Langley left legacies, as did probably members of the families of Mortimer, Nevill, Kemp, Grey, Arundell, and Vernon. Several Wardens became Priors of Durham: Gilbert Kymer, physician to Duke Humphrey, and ten years Chancellor of the University, lived in the College. The Priors regulated the College from time to time; in a letter of 1467 some strong language is addressed to a fellow who had indulged in riotous living till “vix superest operimentum corporis et grabati.”