In the treaty with West Germany, signed in December 1970 at the end of Gomułka's period in office, Germany recognized the post-World War II borders, which established a foundation for future peace, stability and cooperation in Central Europe. In the same month, economic difficulties led to price rises and subsequent bloody clashes with shipyard workers on the Baltic coast, in which several dozen workers were fatally shot. The tragic events forced Gomułka's resignation and retirement. In a generational replacement of the ruling elite, Edward Gierek took over the Party leadership and tensions eased.