Develop a musical composition by integrating the alphabetically represented musical pattern and the supplied melodic theme.
X:1
L:1/4
Q:1/2=120
M:2/2
K:G
['c B']  
X:1
L:1/4
Q:1/2=120
M:2/2
K:G
|:"^A""G" G2 B2 |"^/" d3 c/B/ |"Am" c e c A |"D7" F A F D |"G" G2 B2 |"^/" d3 g |"A7" f e d ^c | 
"D" d2 D2 ::"^B""D" d2 f2 |"D7" a3 c |"G" c B g B |"Am" c2 A c |"G/B" d e f g |"Am" c B e c | 
"D7" B A G F |"G" G2 G,2 :|  