▁sp ars ely ▁populated . ▁A ▁new ▁period ▁in ▁hill fort ▁development ▁started ▁during ▁the ▁ 5 th - 8 th ▁centuries ▁AD , ▁when ▁many ▁new ▁hill fort s ▁appeared , ▁in ▁most ▁cases , ▁along ▁the ▁main ▁tr ades ▁routes ▁- ▁rivers . ▁During ▁the ▁ 1 0 th - 1 1 th ▁centuries , ▁some ▁of ▁the ▁hill fort s ▁became ▁military ▁for tr esses ▁with ▁strong ▁fort ifications ▁( like ▁hill fort s ▁in ▁T ē rv ete , ▁Tal si , ▁Me ž ot ne ). ▁Some ▁of ▁them ▁are ▁considered ▁important ▁political ▁cent res ▁of ▁the ▁local ▁pe op les , ▁who ▁in ▁this ▁period ▁were ▁subjects ▁of ▁serious ▁social ▁political ▁changes . ▁That ▁period ▁was ▁known ▁for ▁un rest ▁and ▁military ▁activities , ▁as ▁well ▁as ▁power ▁strugg les ▁between ▁local ▁arist ocracy . ▁Most ▁of ▁the ▁Lat v ian ▁hill fort s ▁were ▁destroyed ▁or ▁abandoned ▁during ▁the ▁Liv onian ▁Cr us ade ▁in ▁the ▁ 1 3 th ▁century , ▁but ▁some ▁were ▁still ▁used ▁in ▁the ▁ 1 4 th ▁century . ▁In ▁total , ▁there ▁are ▁about ▁ 4 7 0 ▁hill fort s ▁in ▁Lat via . ▁ ▁Lat g ale ▁▁ ▁As otes ▁hill ▁fort ▁▁ ▁G ribu ļ u ▁hill ▁fort ▁ ▁J ers ik as ▁hill ▁fort ▁ ▁Kal v ā nu ▁hill ▁fort ▁ ▁K iu ku ▁hill ▁fort ▁ ▁Mark ov as ▁hill ▁fort ▁ ▁Rat in ī ku ▁hill ▁fort ▁ ▁R ē ze kn