▁or ▁regarding , ▁Historic ▁Ser bia ▁or ▁Ser bs . ▁ ▁Mon arch s ▁▁ ▁The ▁following , ▁of ▁the ▁V last im iro vić ▁dynast y , ▁ruled ▁Ser bia : ▁ ▁Pet ar ▁( 8 9 2 – 9 1 7 ) ▁ ▁Pav le ▁( 9 1 7 – 9 2 1 ) ▁ ▁Z ah ar ija ▁( 9 2 1 – 9 2 4 ) ▁ ▁Č as lav ▁( 9 2 7 – 9 6 0 ) ▁ ▁Events ▁▁▁ 9 1 4 – 9 1 7 ▁ ▁By z ant ines ▁sends ▁en vo ys ▁to ▁Ser bs ▁and ▁Mag y ars ▁regarding ▁an ▁al liance ▁against ▁the ▁Bulg ari ans . ▁ ▁Prince ▁Pet ar ▁of ▁Ser bia ▁an ne xes ▁Bos nia ▁and ▁P ag ania . ▁ ▁Prince ▁Pet ar ▁comes ▁into ▁conflict ▁with ▁Michael ▁of ▁Z ah um l je . ▁ ▁Michael ▁war ns ▁the ▁Bulg ari ans ▁about ▁the ▁Ser bian - By z antine ▁al liance . ▁▁ 9 1 7 ▁ ▁End ▁of ▁ 2 0 - year - pe ace ▁between ▁Ser bia ▁and ▁Bulg aria ; ▁ ▁Prince ▁Pet ar ▁def ends ▁an ▁attack ▁by ▁his ▁cousin ▁and ▁Bulgar ian ▁al ly ▁Pav le . ▁ ▁Prince ▁Pet ar ▁is ▁captured ▁by ▁Bulgar ian ▁gener als , ▁sent ▁to ▁j ail ▁in ▁Bulg aria , ▁and ▁dies ▁within ▁a ▁year . ▁ ▁Pav le ▁becomes ▁the ▁Ser bian ▁Prince . ▁▁ 9 2 0 ▁ ▁Prince