Complex sentence: Originally developed by MathCore Engineering as "MathModelica" it was acquired by Wolfram Research on March 30,2011 and re-released as "Wolfram SystemModeler" on 23 May 2012 with improved integration with Wolfram Research's Mathematica software.
Split into simpler sentences: Originally developed by MathCore Engineering as "MathModelica", it was acquired by Wolfram Research on March 30,2011. It was then re-released as "Wolfram SystemModeler" on May 23,2012, with improved integration with Wolfram Research's Mathematica software.