Who are the present-day owners of Carlow Castle ?, is it possible that the Crown retains ownership ? According to a Lease from King James dated 1604 Donough O' Brien 4th Earl Thomond was to hold - * estate in fee-simple for ever of the Manor of Catherlogh, at the yearly rent of £23. Reserving and excepting out of the said grant the Castle of Catherlogh. The said Donough and his son and the longer liver of them to have the Constableship of the said Castle of Catherlogh, with all the entertainments as Robert and William Hartpole lately enjoyed*.