sentences:  Alexander Winiwarter obtained his medical doctorate in 1870 at the University of Vienna, and worked as a surgical assistant at the Vienna University Clinic under Theodor Billroth, a pioneer in the field of modern surgical practices.Later, he became head of the surgical department at the "Kronprinz-Rudolf-Kinderspitals" (Crown Prince Rudolf Children's Hospital), and in 1878 relocated to Belgium, where he became a professor of surgery at the University of Liège.Subsequently, he acquired Belgian citizenship.