Rabbenu Tam's name was יעקב בן מאיר. Why then is he known as Rabbenu Tam?
Tosafos Rebbeinu Peretz (in Pesachim 38a) refers to הר"ר דיילקרויישא מאורליינש. Does anyone know who this is, or at least how his name is pronounced? (It looks like it could be "R' Delacroix of ...