In July of the following year, Byzantine reinforcements attacked the blockading force, harassing it with mounted archers and spreading discord among its ranks through diplomatic techniques.
The Normans first arrived in southern Italy in 1015 from northern France and served local Lombard lords as mercenaries against the Byzantine Empire.
[11] Meanwhile, he sent an ambassador to the Byzantine court with orders to demand proper treatment for Helena and to win over the Domestic of the Schools, Alexios Komnenos.
[17] Historian Robert Holmes states: "The new knightly tactic of charging with the lance couched—tucked firmly under the arm to unite the impact of man and horse—proved a battle-winner.
He also learned that the Holy Roman Emperor, Henry IV, was at the gates of Rome and besieging Pope Gregory VII, a Norman ally.
The Byzantines then resorted to organizing a plot within the Norman army, spearheaded by the officers Peter of Aulps, Renaldus, and William, who were accused of attempting to defect.
In the early winter of 1082, Alexios managed to obtain a mercenary force of 7,000 soldiers from the Seljuq Turkish sultan Suleiman ibn Qutulmish.
Alexios continued to raise troops in Constantinople, while in late 1082 the Patriarch of Jerusalem Euthymius was sent to Thessalonica, where he mustered an additional force and attempted to broker a deal with the Normans.
[28] The Byzantines avoided a direct engagement with the Normans, passing south-west of Larissa and arriving at Trikala in early April, without encountering any resistance.
Byzantine scouts managed to apprehend a local man, who provided them with crucial information about the topography of the areas surrounding Larissa.
Following a brief engagement the Byzantines made a feigned retreat, leading the unsuspecting Normans to a place called Lykostomion (Wolf's Mouth), where Alexios awaited with a unit of elite cavalry.
When a small force of peltasts (light infantry) and mounted archers began to harass them from another direction, Brienne's cavalry turned their attention towards them.
[29] Discord continued to spread in the Norman army, as its officers demanded two and half years' worth of payment arrears, a sum Bohemond did not possess.