▁in ▁Bos nia ▁and ▁Herz egov ina . ▁B ism ar ck ▁became ▁the ▁target ▁of ▁hat red ▁of ▁Russian ▁national ists ▁and ▁Pan - S lav ists , ▁and ▁found ▁that ▁he ▁had ▁tied ▁Germany ▁too ▁closely ▁to ▁Austria ▁in ▁the ▁B alk ans . ▁ ▁In ▁the ▁long - run , ▁t ensions ▁between ▁Russia ▁and ▁Austria - H ung ary ▁intens ified , ▁as ▁did ▁the ▁national ity ▁question ▁in ▁the ▁B alk ans . ▁The ▁Congress ▁succeeded ▁in ▁keeping ▁Ist an bul ▁in ▁Ott oman ▁hands . ▁It ▁effectively ▁dis av owed ▁Russia ' s ▁victory . ▁The ▁Congress ▁of ▁Berlin ▁returned ▁to ▁the ▁Ott oman ▁Empire ▁territ ories ▁that ▁the ▁previous ▁treat y ▁had ▁given ▁to ▁the ▁Princi p ality ▁of ▁Bulg aria , ▁most ▁not ably ▁Mac ed onia , ▁thus ▁setting ▁up ▁a ▁strong ▁re van ch ist ▁demand ▁in ▁Bulg aria ▁that ▁in ▁ 1 9 1 2 ▁led ▁to ▁the ▁First ▁B alk an ▁War ▁in ▁which ▁the ▁Tur ks ▁were ▁defeated ▁and ▁lost ▁nearly ▁all ▁of ▁Europe . ▁As ▁the ▁Ott oman ▁Empire ▁gradually ▁sh rank ▁in ▁size , ▁military ▁power ▁and ▁wealth , ▁many ▁B alk an ▁Muslim s ▁migr ated ▁to ▁the ▁emp ire ' s ▁remaining ▁territory ▁in ▁B alk ans ▁or ▁to ▁the ▁heart land ▁in ▁An atol ia . ▁Muslim s ▁had ▁been ▁the ▁majority ▁in ▁some ▁parts ▁of ▁Ott oman ▁Empire ▁such ▁as ▁the ▁Crime a , ▁the ▁B alk ans ▁and ▁the ▁C au cas us