some point during the castles' short lifespan. 19 arrowheads were found buried deep into the ramparts and gates. Combined with the three mass graves, this is taken as solid evidence. The slain soldiers were quickly buried in the massgraves, many of them showing deep cuts and lethal wounds from close combat weapons. Strontium analysis of the skeletal remains has revealed that a larger part of the dead, originated from what we now know as Norway and Poland and are therefore thought to have been foreign mercenaries, stationed here as castle guards. This discovery falls in line with Harald Bluetooth's strong alliance with the Obotrite Slavs through his marriage with Tove, daughter of prince Mstivoj. Harald later fled to the town of Wolin (then known as Jumne), where he died from his wounds after fighting off his persecutors in 986-87 AD. Dating Datings by dendrochronology, have found the wood used for the constructions to have been felled in the fall of 980 AD and subsequently used for building, presumably in the spring of 981 AD. The rather short construction time and the complete lack of any signs of maintenance, indicate an only short use of the buildings of no more than perhaps 10–15 years. Parts of the fortress, such as the outer eastern rampart was probably never completed before the site was abandoned. Archaeological finds shows that Trelleborg was under attack at some point, resulting in several dead soldiers and signs of fire, suggests the castle might have been destroyed by fire. The regions around the gates show signs of longer usage though. Older, previous datings put the castle near the year 1000 AD. Today The landscape surrounding the Trelleborg, has changed considerably since the Viking Age, due to a land rise known as post-glacial rebound, affecting this part of the world, and the previous swamp has shrunk to a small bog, while the two rivers of Vårby Å and Tude Å, has reduced to narrow streams. In 1948, one of the longhouses was reconstructed on the site, but more recent investigations have since led to other opinions on its true original design. Today the site of the Trelleborg is an open-air museum with some buildings for exhibits. The museum was established in 1995, and from 1999-2004 the Danish historian Kåre Johannessen was the curator at the museum. Slagelse Municipality has recently granted DK 25 mio. to update Trelleborg Museum with