sentences:  Initially based in Weston-Super-Mare, UK, it moved its headquarters to Bristol.Alterian floated on the techMARK index of the London Stock Exchange in 2000
  
  In May 2006, Alterian acquired email marketing software vendor Dynamics Direct
  
  In July 2008, Alterian acquired Mediasurface, a UK based Web Content Management software vendor for $35.6 million
  
  In July 2011, Alterian appointed Heath Davies as CEO, replacing David Eldridge who stepped down from the board in April 2011, along with the other founders Tim McCarthy and Mike Talbot later the same year.In December 2011, Alterian was acquired by SDL International, a company best known for its language services and technology and its Web Content Management solution SDL Tridion.