Theme A LEGO Theme is a way to classify LEGO sets on the main subject they cover . Set s are sorted by their theme . Prominent examples include Batman , Star Wars , Harry Potter , and BIONICLE . History . First LEGO System themes ( 1978 – 1999 ) . With the introduction of the minifigure - compatible " System " line in 1978 , LEGO established the three major themes " Town " , " Castle " and " Space " , inside each of which were later added several new subthemes , that mostly consisted of new distinct factions of minifigures and were all related to the respective main theme ' s core subjects . With " Boats " and " Trains " , two minor themes where introduced that complemented " Town " but were not counted as parts or subthemes of it . Another unique theme was Model Team from 1986 , whose sets focussed on more or less accurate scale reproductions of real world vehicles and were not designed to be minifigure - compatible . Beginning with " Pirates " in 1989 , LEGO added additional main themes to the " LEGO System " line that stood beside the three initial main themes . These four major theme made up the bulk of the LEGO System sets of that era and were also the most popular themes . Another minor System theme Belville was introduced in 1994 , which contained larger figure and more specially - designed bricks . The next addition was " Aquazone " in 1995 followed by " Western " in 1996 . The odd " Time Cruisers " line from the same year is considered a subtheme of " Town " . The , now six , major minifigure - themes ( " Town " , " Castle " , " Space " , " Pirates " , " Aquazone " and " Western " ) were subjected to bigger changes in 1999 : " Space " , " Pirates " , " Aquazone " and " Western " were discontinued for the time being . " Castle " was rebranded to " Knights ' Kingdom " . " Town ' s " core subjects were outsourced to " Town Jr . " and later " City Center " , while still being complemented by different subthemes which were in most cases only remotely related to city - life . An exception was the smaller " Adventurers " theme from 1998 that was complemented with different subthemes until its eventual discontinuation in 2004 . Smaller themes and licensing ( 1999 onwards ) . Instead of slowly adding new factions and sets to existing main themes , most themes were now self - contained series of sets that in most cases had all of its sets released in its first year and only lasted for one or two more years . One of these new themes was " Rock Raiders " from 1999 and " Life on Mars " from 2001 , which was a shortlived revival of the old " Space " theme . The other side of the medal were themes that were based on popular media franchises like " Star Wars " and " Harry Potter " . Those themes would regularly see new releases over the timespan of several years . Another possibility of releasing sets based on licenses was the " Studios " theme . Nevertheless , there were still some original LEGO themes that ran for several years and were regularly updated with new sets , like " Alpha Team " that ran from 2001 to 2005 and to a smaller extent " Knights ' Kingdom II " that saw new releases from 2004 to 2006 . Relaunch of classic themes ( 2005 onwards ) . With the introduction of " City " in 2005 , the constant rebranding of the " Town " theme in the years after 1999 ended . It also marked the first true revival of one of the classic major themes since the initial concept of complementing a consistent long running theme by regular releases of new sets saw a renaissance as well . Other recent themes were " Castle ( 2007 ) " and the continuation of " Pirates " . " Space " saw a partial revival in the form of " Mars Mission " ( 2007 - 2008 ) and the new " Space Police " from 2009 .