This is a massive family tree put together by the "Finding Your Roots" program on PBS. It traces the Gyllenhaal lineage back for nearly a thousand years, in part by using modern DNA analysis. In 2012, Maggie Gyllenhaal was a guest on the show, hosted by noted Harvard historian and author Henry Louis "Skip" Gates Jr.
"Finding Your Roots" poured through historic records, interviewed family members and visited key place in the family histories. "When the paper trail runs out, we turn to the latest advances in DNA genetic analysis,'' Gates said as he introduced the findings.
"We showed Maggie her family tree, which stretches back almost a thousand years,'' he said. "When we follow these lines into the past they travel through many of the most important events in European history, in this case, back to the times of the first crusade.''
This genealogy chart is packed with information, but it's a little hard to read in this digital form, since it's so large. If you expand the graphic as much as possible, you can make out most of the people and dates. It may help to use a magnifying glass.