Leukon had inherited several wars from his father, including one against the
Ixomatae, led by queen
Tirgatao, ending with the unsuccessful siege to Theodosia that claimed his father's life. He and his brother Gorgippos made peace with the Ixomatae and focused their attentions to the west.
Siege of Theodosia (c.365 BC) and
Chersonesus. After his father's death and his ascendance to the throne, Leukon laid siege the city of Theodosia twice. The first siege ended in a Bosporan defeat due to Tynnichus, a general sent by Heraclea Pontica, to relieve the city, which he accomplished, despite inferior numbers, due to trickery.
Siege of Theodosia (c.360 BC) Leucon besieged Theodosia again 5 years later in a surprise attack, before the city could receive relief aid from the
Heracleotes. It is possible that the Heracleotes withdrew before Leucon attacked due to a change of government from oligarchy to tyranny under
Clearchus. He was then attacked by the Heracleotes in his own territory. Leucon, noticing that his own troops could be routed easily, positioned his Scythian soldiers in the rear and gave clear instructions that his men were to be struck down if they fled. This precaution helped his army defeat the Heracleotes. Shortly after his victory, Leucon made a peace treaty with the Heracleotes, ending the war.
Annexation of the Sindike Kingdom Leucon then turned his eye to the
Sindike Kingdom, where there had been a dynastic dispute between
Hecataeus, the king of the Sindi, and his son, Octamasades who had taken power from his father. Before the
Battle of Labrytai, Leucon said he “made a vow to erect a victory monument, not to the local Apollo of Labrys, but to the supreme deity and patron of all the Bosporans, Apollo the Healer”. After defeating Octamasades, it is possible Leucon persuaded Hecataeus to surrender the kingship to him, as he was proclaimed "king of all the Sindike" shortly thereafter. ==Later reign==