In December 1189 King Sancho I,  made a donation of the Castle of Alvor to the monastery of Santa Cruz of Coimbra wich "Nicolaus Sylvensis episcopus confirmat " ( Brito, Monarchia  Luysitania, IV, fol.15);


in february  1191 the king made a donation to the monastery of Alcobaça, and among the bishops attesting the charter appears"Niculaus Sylvensis " (ibid,fol. 259-260 );  in March 1190, bishop Nicolaus himself, at the kings request, made a donation of the of the ius ecclesiasticum of the castle of Lagos to the monastery of Saint-Vincent de Fora at Lisbon, the king himself having already given the castle ( Nicolao de Santa Maria, Chronica da Ordem dos Cónegos Regnantes, do patriarcha S. Agostinho, Lisboon,1668, II, 129 ) and among the canons of Silves who consent to this donation are " William, the dean, Peter the treasurer, and Lambert, the archdeacon,) some of whom, at least, may well have been fellow Flemings, who remained at Silves with Nicholaus, when the rest of cruzaders departed. 

See Fortunato de Almeida, História da Igreja em Portugal ( Coimbra 1910-24)