In the Germany of the 19th century, Geiger and Samuel Holdheim, along with Israel Jacobson and Leopold Zunz, stood out as the founding fathers of Reform Judaism. Geiger was a more moderate and scholarly reformer, seeking to found this new branch of Judaism on the scientific study of history, without assuming that any Jewish text was divinely written.
Geiger was not only a scholar and researcher commenting on important subjects and characters in Jewish history, he was also a rabbi responsible for much of the reform doctrine of the mid-19th century. He contributed much of the character to the reform movement that remains today. Reform historian Michael A. Meyer has stated that, if any one person can be called the founder of Reform Judaism, it must be Geiger.»
Abraham Geiger - Wikipedia, the free encyclopedia