 Ranulf worked to complete the cathedral which his predecessor , William de St @-@ Calais , had begun ; fortified Durham with a wall around Durham Castle , built Norham Castle to help defend the Tweed River ; and endowed the collegiate church of Christchurch , Hampshire . He built or expanded other churches , including the one at Christchurch in Hampshire which he had endowed , and St. Martin 's in Dover . The first stone bridge at Durham was completed by his instruction in 1120 , the so @-@ called <unk> Bridge , a bridge described as " of wonderful workmanship . " He cleared and levelled the Palace Green in Durham between the castle and the cathedral . While the chroniclers mainly condemned Ranulf for his morals , his own cathedral chapter held him in high esteem because of his building activities and his defence of the rights of Durham . Although he usurped some of the income of the cathedral chapter , the money from those rights was used to complete the cathedral rebuilding , and later restored the income to the monks as well as increasing the endowment . At his death , the cathedral walls were complete up to " the covering " , which probably means the vault instead of the roof . 
