 Beer 's first keyboard instructor was Franz Lauska , a pupil of Johann Georg Albrechtsberger and a favoured teacher at the Berlin court . Beer also became one of Muzio Clementi 's pupils while Clementi was in Berlin . The boy made his public debut in 1801 playing Mozart 's D minor Piano Concerto in Berlin . The Allgemeine musikalische Zeitung reported : ' The amazing keyboard playing of young Bär ( a Jewish lad of 9 ) , who carried off the difficult passages and other solo parts with aplomb , and has fine powers of rendition even more rarely found in one of his age , made the concert even more interesting ' . 
 Beer <a href='null_genetive' title='1'><mark>'s</mark></a>first keyboard instructor was Franz Lauska , a pupil of Johann Georg Albrechtsberger and a favoured teacher at the Berlin court . Beer also became one of Muzio Clementi <a href='null_genetive' title='2'><mark>'s</mark></a>pupils while Clementi was in Berlin . The boy made his public debut in 1801 playing Mozart <a href='null_genetive' title='3'><mark>'s</mark></a>D minor Piano Concerto in Berlin . The Allgemeine musikalische Zeitung reported : ' The amazing keyboard playing of young Bär ( a Jewish lad of 9 ) , <a href='null_relcl' title='4'><mark>who</mark></a>carried off the difficult passages and other solo parts with aplomb , and <a href='got' title='5'><mark>has</mark></a> fine powers of rendition even more rarely found in one of his age , made the concert even more interesting ' . 
Beer  first keyboard instructor was Franz Lauska , a pupil of Johann Georg Albrechtsberger and a favoured teacher at da Berlin court . Beer also became one of Muzio Clementi  pupils while Clementi was in Berlin . Tdaboi made his public debut in 1801 playin Mozart  D minor Piano Concerto in Berlin . The Allgemeine musikalische Zeitung reported : ' The amazin keyboard pplayinof young Bär ( a Jewish lad of 9 ) , carried offf the difficult passages and other solo parts w aplomb , and got fine powers of rendition even more rarely found in one of his age , made the concert even more interesting ' .