Malcolm succeeded to the throne after killing his predecessor, Kenneth III, and allegedly secured his territory by defeating a Northumbrian army at the battle of Carham (c. 1016); he not only confirmed the Scottish hold over the land between the rivers Forth and Tweed but also secured Strathclyde about the same time. Eager to secure the royal succession for his daughter's son Duncan, he tried to eliminate possible rival claimants; but Macbeth, with royal connections to both Kenneth II and Kenneth III, survived to challenge the succession.