a new light over "Golden Gate": after 1870, alsacians had the choice ("optants") to remain french and to leave their home... Lots fled to vicinity of Alsace Lorraine, Switzerland and America (USA & Canada) An internet tool(site) permits to find them. The proof of their "journey"(<1892) is not really on line although announced by me on this forum. So, from this day, when an ancestor is searched, several tools have to be used. But, this is my "business"
For the ones become german after 1870, proofs of their journey has to searched on german web sites (cf passengers's list from Hamburg)