▁the ▁Stone ▁Age ▁( 4 2 0 0 – 1 8 0 0 ▁B CE ) ▁humans ▁started ▁to ▁use ▁more ▁station ary ▁settlement s , ▁solid ▁buildings ▁standing ▁on ▁strong ▁pol es ▁d ril led ▁into ▁the ▁ground , ▁even ▁if ▁the ▁access ▁to ▁food ▁still ▁made ▁mig rat ory ▁periods ▁necessary . ▁ ▁Gra ves ▁got ▁more ▁elaborate ▁as ▁gr inned ▁axes ▁made ▁of ▁carefully ▁selected ▁and ▁often ▁imported ▁rocks ▁accompanied ▁the ▁dead ▁together ▁with ▁cer am ics , ▁fancy ▁gar ments , ▁and ▁other ▁impress ive ▁objects . ▁ ▁Emer gence ▁▁ ▁The ▁first ▁town ▁in ▁the ▁Lake ▁M ä lar en ▁region ▁was ▁und ou bt edly ▁Bir ka ▁on ▁B jör kö ▁island ▁about ▁ 2 0   km ▁west ▁of ▁present - day ▁Stockholm . ▁ ▁F ounded ▁in ▁the ▁late ▁ 8 th ▁century , ▁it ▁was ▁described ▁by ▁R im bert , ▁Arch bishop ▁of ▁Hamburg - Bre men , ▁who ▁wrote ▁about ▁his ▁prede cess or ▁An sg ar ' s ▁mission ary ▁jour ne ys ▁c . ▁ 8 3 0 ▁and ▁ 8 5 0 . ▁ ▁For ▁unknown ▁reasons , ▁Bir ka ▁was ▁desert ed ▁around ▁ 9 7 5 . ▁ ▁Short ly ▁there after , ▁S igt una ▁appeared ▁on ▁the ▁northern ▁sh ores ▁of ▁M ä lar en . ▁ ▁Loc ated ▁on ▁the ▁main ▁navig able ▁approach ▁to ▁U pp s ala , ▁S igt una ▁is ▁believed ▁to ▁have ▁been ▁designed ▁as ▁mission ary ▁out post