Swedish history dates back to the Viking Age, around the 8th to 11th centuries, when the Norsemen explored and traded across Europe. The establishment of the Kingdom of Sweden occurred in the 12th century, leading to the unification of various tribes and regions. During the 17th century, Sweden emerged as a major European power, known for its military strength and territorial expansion, particularly during the Thirty Years' War. However, by the 18th century, Sweden faced military defeats and territorial losses, leading to a period of neutrality that continues to this day.