commonwealth forces were engaged in numerous conflicts in the south (against the ottoman empire), the east (against the tsardom of muscovy, later known as the russian empire) and the north (the kingdom of sweden); as well as internal conflicts (most notably, numerous cossack uprisings). for the first century or so, the commonwealth military was usually successful, but became less so from around the mid-17th century. plagued by insufficient funds, it found itself increasingly hard-pressed to defend the country, and inferior in numbers to the growing armies of the commonwealth's neighbors.