Answer by taking a quote from the following article:

Nobuo Uematsu (Zhi Song  Shen Fu , Uematsu Nobuo, born March 21, 1959) is a Japanese video game composer, best known for scoring most of the titles in the Final Fantasy series by Square Enix. He is considered to be one of the most well known composers in the video game industry. Sometimes referred to as the "Beethoven of video games music", he appeared five times in the top 20 of the annual Classic FM Hall of Fame. Uematsu, a self-taught musician, began playing the piano at the age of twelve, with English singer-songwriter Elton John as his biggest influence.

Uematsu left Square Enix in 2004 and formed his own production company, Smile Please. He later founded the music production company and record label Dog Ear Records in 2006. The reason for Uematsu's departure was that the company moved their office from Meguro to Shinjuku, Tokyo, and he was not comfortable with the new location. Also, he cites the fact that he had reached an age where he should gradually take his life into his own hands. He does, however, continue to compose music as a freelancer for Square Enix. In 2005, Uematsu and several members of The Black Mages created the score for the CGI film Final Fantasy VII Advent Children. Uematsu composed only the main theme for Final Fantasy XII (2006); he was originally offered the job of creating the full score, but Sakimoto was eventually assigned as the main composer instead. Uematsu was also initially going to create the theme song for Final Fantasy XIII (2010). However, after being assigned the task of creating the entire score of Final Fantasy XIV, Uematsu decided to hand the job over to the main Final Fantasy XIII composer, Hamauzu.  Uematsu also works closely with Sakaguchi's development studio Mistwalker, and has composed for Blue Dragon (2006), Lost Odyssey (2007), Away: Shuffle Dungeon (2008); The Last Story (2011); and Terra Battle (2014). He also wrote music for the cancelled game Cry On.  Uematsu created the main theme for the multi-composer game Super Smash Bros. Brawl in 2008. He then composed the music for the 2009 anime Guin Saga; this marked the first time he provided a full score for an animated series. Uematsu recently contributed music and storyline to an e-book titled called "Blik-0 1946". He is currently working on soundtracks for multiple games, including Project Phoenix.  Uematsu appeared five times in the top 20 of the annual Classic FM Hall of Fame. In 2012, "Aerith's Theme", written by Uematsu for Final Fantasy VII, was voted into the number 16 position in the annual Classic FM (UK) "Hall of Fame" top 300 chart. It was the first time that a piece of music written for a video game had appeared in the chart. In 2013, music from the Final Fantasy series received even greater support and was voted into the third position on the Classic FM Hall of Fame. Uematsu and his Final Fantasy music subsequently appeared at number seven in 2014, number nine in 2015, and number 17 in 2016.

What did Uematsu do as a freelancer/
created the score