They had their army formations like trained soldiers.
The hosts, when in order of battle, were divided into sveitir (detachments), and a number of these formed a fylking; the strength of each probably varied according to the number of men who took part in the war.
“King Olaf made the following speech to his host before the battle of Stiklastadir:—‘We have a large and fine host. Now I will tell you how I want to array my men. I want to let my standard move forward in the middle of the host, and my hird and gestir shall follow it, together with those who joined me from Upplönd and Thrándheim. To the right of my standard Dag Hringsson shall stand, and the men with whom he joined us. He shall have another standard. To the left of my fylking shall stand the men from the King of Sweden and all those who joined us in Sviaveldi. They shall have the third standard. I want my men to form detachments, and friends and kinsmen shall stand together, for then each will defend the other best, and they will know each other.
“‘We shall mark all our men by making a war-sign on our helmets and shields, namely, paint on them the holy cross in white.
“‘When we come forward into battle we shall all have the same watchword: “Forward, forward, Christ-men, cross-men, king’s men.” We must have thin arrays if we have fewer men, for I do not want them to surround us.
“‘Now form sveitir. Then the sveitir shall be put together to form fylkings, and each man must then know his place and mind in what direction he stands from the standard to which he belongs. We will keep our fylking and be fully armed day and night till we know where we meet the bœndr.’ When he had spoken they arrayed themselves, and arranged as the king had told them” (St. Olaf’s Saga, c. 216).
“The chief Kalf Arnason raised his banner, and placed his huskarls and Harek of Thjotta and his men round it. Thorir Hund with his host was in front of the host, and in front of the standards” (St. Olaf’s Saga, ch. 233).
Standards, often very elaborately worked, were used both on sea and land; some of these had great reputations, and picked warriors were always chosen to carry them, each fylking having one. The poets or scalds seem to have stood close to them in the shieldburg.
“He, Egil Ullserk, was an old bondi who had been a great warrior, and for a long time carried the banner of Harald the Fairhaired. He said: ‘I feared for some time, while this great peace lasted, that I should die from old age on my bench, and I wished rather to fall in battle with my chief; now it may happen so’” (Heimskringla, Hakon the Good, c. 23).
“One summer the Scotch Jarl Finnleik staked out with hazels a battle-field for Sigurd at Skidamyri on an appointed day. Sigurd went to consult his mother, who knew many things. He told her that there would be against him not less than seven to one. She replied: ‘I would have raised thee in my wool chest if I had been certain that thou wouldst live for ever. Better is it to die with honour, than to live in shame. Take this merki (standard), which I have made with my best skill, and which I believe will be victorious for those before whom it is carried, but deadly to him who carries it.’ The standard was made with great hard-work and renowned skill. It was in the shape of a raven, and when the wind blew on it it seemed as if the raven spread his wings. Sigurd Jarl became very angry at his mother’s words, and gave the Orkney islanders their odals to help him; he went against Finnleik Jarl at Skidamyri, and both arrayed their men. When the fight began, the Scots slew the standard-bearer of Sigurd Jarl; he appointed another to carry it, but after a while he fell; three standard-bearers were slain, but the Jarl was victorious” (Flateyjarbók, vol. i.).