 Flawil is first mentioned in 858 as "Flawilare marcho".Several of the surrounding hamlets were also mentioned in about the same era.Alterswil was first mentioned in 858 as "Altiricheswilae", Oberglatt in 731 as "villa Clata" and in 1316 as "Obren Glat" and Burgau in 964 as "Purchouva".