However, the expected peace due to this marriage was short-lived. In early 1265 Brandenburg occupied the main city of Santok and broke the previous agreement. Thanks to an immediate diplomatic intervention, Bolesław soon signed a new treaty with Brandenburg, under which Greater Poland burned the fortress built in Drezdenko, and Brandenburg also burned his fortress in Santok. But in 1269 war with Brandenburg erupted again. They built a fortress in Sulęcin, and in response Bolesław did the same thing in Międzyrzecz. The invasion of Międzyrzecz launched by the Margraves of Brandenburg was successfully repulsed by Bolesław, who in December 1269 could advance to Lubusz and in addition, during this expedition burned several fortresses, included the one newly built in Sulęcin. Both sides made a new agreement and were restored the fortress in Santok (from Brandenburg) and Drezdenko (from Greater Poland). The latter was captured by Brandenburg in 1270. For this reason, in the spring of 1271 Bolesław organized a major military expedition against Santok and Neumark, ravaging this land terribly, but he could not recover the lost domains.