This task involves annotating the answer type to a given question that involve some kind of complex reasoning (including numerical reasoning). Note that the questions require looking at more than one part of the passage to answer. There are 3 possible answer types (i) spans, (ii) numbers and (iii) dates. If the answer can be found in the passage, label it as "span". If the answer is a number, label as "number". Similarly, label "date" if you think the answer to the given question is a date.

Passage: Scandinavians maintained trade relations and other links with Novgorod from the Viking Age onwards. Merchants from Gotland operated both their own trading house and the St. Olof church in Novgorod. Scandinavians also carried out isolated raids on Novgorod. Eirikr Hakonarson raided Ladoga in 997, and his brother Sveinn Hakonarson followed suit in 1015. After the marriage of Yaroslav I to Ingegerd of Sweden in 1019, Ladoga became a jarldom in the orbit of Kievan Rus. It was ruled by Ragnvald Ulfsson, the alleged father of King Stenkil of Sweden . Dynastic marriages took place between Russian and Scandinavian royal families - for example, in the 1090s Stenkil's granddaughter Christina married Mstislav of Novgorod, upon whose death in 1132 Novgorod seceded from Kievan Rus. The major turning point into more permanent conflict between Sweden and Novgorod arrived with Sweden's firmer organization into the Catholic Church in the 12th century and papal involvement in crusades against lands controlled by the Orthodox Church.
Question: Which brother raided Ladoga first, Sveinn Hakonarson or Eirikr Hakonarson?
span