Asser was a member of the Hvide noble family and had been raised together with Valdemar's father Canute Lavard.

[2][3][4][5] In 1146, when Valdemar was fifteen years old, King Eric III of Denmark abdicated and a civil war erupted.

[8][9] He reinvented Viking raiding tactics of old to deal with the Wends to the south, which was now optimized for heavy cavalry; this use of amphibious assault was further improved upon by his successor Canute VI.

Around the year 1170, a smaller contingent of the Danish fleet (headed by Valdemar and Absalon) ventured past the mouth of the Oder, where they were ambushed by a Wendish army and fleet under Casimir, at the Julin bridge (modern-day Wolin) hoping to end Danish raiding.

But the Danes outsmarted the Wends and smashed their army and fleet, primarily due to the Danish ships also carrying cavalry.

[11] In 1175, King Valdemar built Vordingborg Castle as a defensive fortress and as a base from which to launch further raids against the German coast.

But even though the entire peasant force surrendered, they still refused to pay tithes, so instead Valdemar had them bring generous gifts and donations to the church.

[13] This concession to the Scanians, that a Jute rules in Jutland and Rugian in Rügen, was then optimized for the rest of the Danish realm.