Can the 16 th and early 17 th centuries in Poland-Lithuania and some other east-central European countries be characterized as a "Golden Age" in human capital? We trace the development of a specific human capital indicator during this period: numeracy. We draw upon new evidence for Poland and Russia from the early 17 th century onwards; and for Belarus, Ukraine, and Lithuania from the 18 th century onwards; controlling for potential selectivity issues. Poland had quite high levels of numeracy during the early 17 th century, but these levels subsequently fell below those of even southern Europe. As in other countries in the area, numeracy levels in Poland were lower than those of western Europe during the 17 th , 18 th , and early 19 th centuries. This finding might support the hypothesis that the second serfdom process, which gained momentum during the 17 th century, was one of the core reasons why human capital accumulation was delayed in eastern Europe. The major wars in the region also had devastating effects on numeracy levels.