Cleomenes III Cleomenes III ( ) was King of Sparta in 235 – 222 BC . He succeeded to the Agiad throne of Sparta after his father , Leonidas II in 235 BC . From 229 BC to 222 BC , Cleomenes waged war against the Achaean League under Aratus of Sicyon . Domestically , he is known for his attempt to reform the Spartan state . After being defeated by the Acheans in the Battle of Sellasia in 222 BC , he fled to Ptolemaic Egypt . After a failed revolt in 219 BC , he committed suicide . Early life . Cleomenes was born in Sparta to King Leonidas II and his wife Cratesicleia and was part of the Agiad dynasty . The exact year of Cleomenes ' birth is unknown but historian Peter Green puts it between 265 BC and 260 BC . In around 242 BC , Leonidas was exiled from Sparta and forced to seek refuge in the temple of Athena after opposing the reforms of the Eurypontid King , Agis IV . Cleomenes ' brother - in - law , Cleombrotus , who was a supporter of Agis , became king . Meanwhile , Agis , having started his reforms went on a campaign near the Isthmus of Corinth which presented Leonidas with an opportunity to regain his throne . He quickly disposed of Cleombrotus , and when Agis returned to Sparta he had him arrested and executed . Following the execution of Agis , Cleomenes - who was around eighteen at the time - was made by his father to marry Agis ' widow , Agiatis , who was a wealthy heiress . According to legend , Cleomenes was hunting when his father sent him a message telling him to return immediately to Sparta . When he returned to the city , he saw that it was being decorated for a wedding and when he asked his father who was getting married , his father replied that Cleomenes was . It was reported that Cleomenes was doubtful about the marriage because his father had Agiatis ' husband executed . The marriage worked out and Agiatis told Cleomenes about Agis and his plan . As king . Early years . On the death of his father , Cleomenes ascended the throne of Sparta in 235 BC . Cleomenes had been inspired by Agis and began reforms . Meanwhile , the Achaean League under the command of Aratus of Sicyon was trying to unite all of the Peloponnese . Upon hearing of Leonidas ' death , Aratus began attacking the cities of Arcadia which bordered Achaea . Plutarch says that Aratus made these moves to see how Sparta stood inclined . In 229 BC , the cities of Tegea , Mantinea , Caphyae and Orchomenus - who were allied with the Aetolian League - come over to Sparta . Historians Polybius and Sir William Smith claim that Cleomenes seized these cities by treachery ; however the translator of Plutarch on Sparta , Richard Talbert , claims he did so at their own request . Later that year , the ephors sent Cleomenes to seize Athenaeum , a border fort on the Spartan border with Megalopolis which was being disputed by both cities ; Cleomenes seized the fort and fortified it . Meanwhile , the Achaean League summoned a meeting of its assembly and declared war against Sparta . In retaliation for fortifying the fort , Aratus made a night attack on Tegea and Orchomenus but when his supporters on the inside failed to help , he retreated hoping to remain unnoticed . Cleomenes discovered the attempted night attack , and sent a message to Aratus asking the purpose of the expedition . Aratus replied that he had come to stop Cleomenes fortifying Athenaeum . Cleomenes responded to this by saying : " if it ' s all the same to you , write and tell me why you brought along those torches and ladders . " Cleomenean War . Cleomenes advanced into Arcadia before being called back by the ephors . When Aratus captured Caphyae , the ephors sent him out again . He ravaged the territory of Argos with an army of 5 , 000 men before being confronted by the new strategos of the Achaean League , Aristomachos of Argos , and his army of consisting of 20 , 000 infantry and 1 , 000 cavalry at Pallantium . Aratus , who accompanied Aristomachos as an adviser , advised him to retreat . Smith agrees with Aratus ' assessment that 20 , 000 Achaeans were no match for 5 , 000 Spartans . This success greatly encouraged Cleomenes and when he heard that Aratus was attacking Sparta ' s ally , Elis , he set off to confront them . The Spartan army fell upon the Achaean army near Mount Lycaeum and rout ed it . Aratus took advantage of a rumour saying that he had been killed in the battle and seized Mantinea . His blow took the war spirit out of the Spartans and they began to oppose Cleomenes ' war effort . Meanwhile , the Eurypontid King of Sparta , Eudamidas III , who was the son of Agis IV and Agiatis died . Cleomenes recalled his uncle , who had fled after Agis ' execution to Messene to assume the throne . However , as soon as he returned to Sparta he was assassinated . Cleomenes ' part in the assassination is unknown with Polybius claiming that he ordered it , but Plutarch disagrees . Having bribed the ephors to allow him to continue campaigning , Cleomenes advanced into the territory of Megalopolis and started to besiege the village of Leuctra . As Cleomenes was besieging the village , an Achaean army under the command of Aratus attacked the Spartans . In the initial attack , the Spartans were repelled . However , Lydiadas of Megalopolis , the cavalry commander , disobeyed Aratus ' order not to pursue the Spartans . As the cavalry scattered as they were trying to cross some difficult terrain , Cleomenes ' skirmishers managed to defeat them . Encouraged by this counter - attack , the Spartans charged the main body of the Achaean army and routed them . Confident of his strong position , Cleomenes began plotting against the ephors . After gaining the support of his stepfather , he embarked his opponents with him on a whirlwind military expedition and when they requested to stay in Arcadia due to exhaustion he returned to Sparta to carry out his plan . When he reached the city , he sent some of his loyal followers to kill the ephors . Four of the ephors were killed , while the fifth , Agylaeus , managed to escape and seek sanctuary in a temple . Having removed the ephors , Cleomenes began his reforms . He first handed over all his land to the state ; he was soon followed by his stepfather and his friends and the rest of the citizens . He divided up all the land and gave an equal lot to every citizen . To increase the declining Spartan citizen body , he made some perioeci , citizens . He trained 4 , 000 hoplites and restored the ancient Spartan military and social discipline as well as equipping his army with the Macedonian sarissa ( pike ) which greatly strengthened the army . Defeat and exile . In 222 BC , Cleomenes was defeated in the Battle of Sellasia by the Achaeans , who received military aid from Antigonus III Doson of Macedon . Cleomenes left Sparta and sought refuge at Alexandria with Ptolemy Euergetes of Egypt , hoping for assistance to regain his throne . However , when Ptolemy died , his son and successor , Ptolemy Philopator neglected Cleomenes and eventually put him under house arrest . Together with his friends , he escaped his house arrest in 219 BC and tried to incite a revolt . When he received no support from the population of Alexandria , he avoided capture by committing suicide . Thus died the man who nearly conquered all of the Peloponnese and is described by William Smith as " the last truly great man of Sparta , and , excepting perhaps Philopoemen , of all Greece . " Cleomenes in Fiction . For an idiosyncratic but historically accurate fictional telling of Cleomenes ' life and death , see Naomi Mitchison ' s " The Corn King and The Spring Queen " ( reference given ) . He is also the subject ( under the name Kleomenis ) of two poems by modern Greek poet Constantine Cavafy , 1928 ' s " In Sparta " and 1929 ' s " Come , O King of the Lacedaimonians " . Both of these dwell on the humiliation of his defeat by Ptolemy . Cleomenes is also one of the characters in the book " Krol Agis " ( " King Agis " ) by the Polish writer Halina Rudnicka , and he is the main character in the two following books by the same author " Syn Heraklesa " ( " Heracles ' son " ) and " Heros w okowach " ( " Hero in manackles " ) .