Foreign policy of the Lascarids and the restoration of the Byzantine empire
John III Ducas Vatatzes (1222-1254). After the death of Theodore I Lascaris, John III Ducas Vatatzes, the husband of his daughter Irene, ascended the throne of Nicaea and reigned from 1222 to 1254. Although his predecessor had laid some foundation for the further development of the state of Nicaea, nevertheless its international position was such as to require urgently the rule of a decisive and energetic man. This man appeared in the person of John Vatatzes.
At that time four states were contending for mastery over the East: the Empire of Nicaea, the Latin Empire, the Despotat of Epirus, and the Bulgarian Kingdom of John Asen II. John Vatatzes external policy, therefore, consisted on the one hand of wars, and on the other of alliances with one or another state. By a stroke of good fortune his three rivals in the Balkan peninsula never acted jointly and decisively, but pursued a vacillating and weakening policy of interstate hostilities, or a policy of transient alliances. John Vatatzes thoroughly succeeded in managing the complicated international situation