So many of us that is very difficult to track them down!! Anyway, I have begun to re-create our family tree - Gil de Lamadrid from Arecibo, Puerto Rico, originally from Santander, Spain. There is a family brach of the Gil de Lamadrid - some of whom have dropped either "de Lamadrid" or "Gil". The family tree I am working on can be found at: http://www.gildelamadrid.info/index2.htmlhttp://www.gildelamadrid.info/index2.html.
I have found several other resources that might be of assistance: