The Christianization of Viken was followed by that of Agder. Any decided opposition the king did not meet until he came to South Hördaland, where a number of mighty chieftains had gathered in the hope of intimidating him. His fearless and resolute behavior, however, impressed them so much that, after some negotiations, they accepted the faith and were baptized. In return for this concession, they demanded of the king that he should give his sister Aastrid in marriage to the young and high-born chief, Erling Skjalgsson of Sole; and as the king thought this marriage in every way desirable, he gave his consent. Encouraged by his success, Olaf hastened on to Tröndelag, where was the old and magnificent temple of Hlade, the principal sanctuary of Norse paganism. Impelled by holy zeal, and heedless of the consequences, he broke down the altar of the gods, burned their images, and carried off their treasures. The Trönders promptly responded to this challenge by sending the war-arrow [A] from house to house, and preparing to fight with the king. Olaf, who had but a small force with him, did not venture to offer them battle; but sailed northward to Haalogaland, where another armed band, under the command of Thore Hjort and Haarek of Thjotta, stood ready to receive him. As discretion was here the better part of valor, the king was in no haste to land, but returned to Tröndelag, where the peasants in the meanwhile had dispersed, and began to build a church in the place where the old temple had stood. He meant to show the Trönders that he was neither discouraged nor frightened, that neither threats nor arms could induce him to desist from his undertaking. With the desire to strengthen his power here, where it most needed strengthening, he began also the building of a royal residence, and laid the foundation of the future city of Nidaros or Drontheim (996). [Footnote A: The war-arrow (_hærör_) was carried by every man to his next neighbor and stuck into his door, as a sign that war was at hand. To send or to cut the war-arrow is, therefore, to send a war message.]