Why did Sparta and Athens hate eachother?

array(10) { [0]=> object(stdClass)#4260 (5) { ["video_id"]=> int(9999999) ["related_video_id"]=> string(11) "Jr8EGJwDCk8" ["related_video_title"]=> string(60) "The Full History of the Peloponnesian War - Athens vs Sparta" ["posted_time"]=> string(19) "1 год назад" ["channelName"]=> string(18) "Kings and Generals" } [1]=> object(stdClass)#4233 (5) { ["video_id"]=> int(9999999) ["related_video_id"]=> string(11) "I7dvEyaguTI" ["related_video_title"]=> string(59) "Why did Sparta Have Two Kings? (Short Animated Documentary)" ["posted_time"]=> string(19) "5 лет назад" ["channelName"]=> string(15) "History Matters" } [2]=> object(stdClass)#4258 (5) { ["video_id"]=> int(9999999) ["related_video_id"]=> string(11) "eNqEgxZN6uw" ["related_video_title"]=> string(31) "Short History of Ancient Greece" ["posted_time"]=> string(27) "6 месяцев назад" ["channelName"]=> string(14) "Magistra Vitae" } [3]=> object(stdClass)#4265 (5) { ["video_id"]=> int(9999999) ["related_video_id"]=> string(11) "pW4VjEg0C60" ["related_video_title"]=> string(50) "Sparta and Athens; The Cold War For Ancient Greece" ["posted_time"]=> string(21) "2 года назад" ["channelName"]=> string(16) "Possible History" } [4]=> object(stdClass)#4244 (5) { ["video_id"]=> int(9999999) ["related_video_id"]=> string(11) "zpr-t4VWyjA" ["related_video_title"]=> string(101) "Как Северная Корея зарабатывает миллиарды (feat. Ланьков)" ["posted_time"]=> string(20) "21 час назад" ["channelName"]=> string(33) "Простая экономика" } [5]=> object(stdClass)#4262 (5) { ["video_id"]=> int(9999999) ["related_video_id"]=> string(11) "D1-WuBbVe2E" ["related_video_title"]=> string(40) "Why The Ancient Greeks Couldn't See Blue" ["posted_time"]=> string(21) "4 года назад" ["channelName"]=> string(11) "AsapSCIENCE" } [6]=> object(stdClass)#4257 (5) { ["video_id"]=> int(9999999) ["related_video_id"]=> string(11) "FHhYenZhXUg" ["related_video_title"]=> string(109) "ОШИБКИ ГАРРИ ПОТТЕРА О КОТОРЫХ ВСЕ МОЛЧАТ - ЧТО ПОШЛО НЕ ТАК?" ["posted_time"]=> string(19) "2 дня назад" ["channelName"]=> string(27) "ЧЕРНЫЙ КАБИНЕТ" } [7]=> object(stdClass)#4267 (5) { ["video_id"]=> int(9999999) ["related_video_id"]=> string(11) "192KLouTZMA" ["related_video_title"]=> string(90) "Игра, опередившая время на десятилетия | The Movies 2005" ["posted_time"]=> string(21) "6 дней назад" ["channelName"]=> string(7) "Amytrip" } [8]=> object(stdClass)#4243 (5) { ["video_id"]=> int(9999999) ["related_video_id"]=> string(11) "4SzoEAOmLng" ["related_video_title"]=> string(24) "Why did Sparta Collapse?" ["posted_time"]=> string(19) "5 лет назад" ["channelName"]=> string(10) "Knowledgia" } [9]=> object(stdClass)#4261 (5) { ["video_id"]=> int(9999999) ["related_video_id"]=> string(11) "Er-vhQ803k4" ["related_video_title"]=> string(145) "КОНФЕДЕРАЦИЯ — против чего боролась и для чего существовала | Звёздные войны" ["posted_time"]=> string(28) "10 месяцев назад" ["channelName"]=> string(28) "Прокрастинация" } }