Few families in medicine can claim that more than one of their members contributed significantly to modern-day clinical and research practices. The Swiss family of His can assert that two of their number, Wilhelm His Sr. (1831-1904) and Wilhelm His Jr. (1863-1934) made advancements in medicine that still have an impact on many areas of research and clinical practice today. In 1865, His focused on embryology research and he introduced the term "endothelium" from his observations in embryology. His invented the microtome in 1866, and named the axonal appendages as dendrites. On the other hand His Jr., in 1893, published a 35-page article that described the activity of the embryonic heart and how this understanding is important in comprehending actions in the adult heart. This article contains the description of his best-known discovery, the now eponymous Bundle of His. Modern researchers and clinicians should consider the importance of the work of both Wilhelm His Sr. and Wilhelm His Jr. Advancements in embryological, histological and cardiovascular electrophysiology research can all trace some input back to this father and son.