Develop a musical composition by integrating the alphabetically represented musical pattern and the supplied melodic theme.
X:1
L:1/8
M:2/2
K:D
['a3 g']  
X:1
L:1/8
M:2/2
K:D
"C" =cegb"D" a3 g |"D" fadf"G" BdGB |"C" =cegb"D" a3 g |"D" faef"G" d2 d^c |"C" =cegb"D" a3 g | 
"D" fadf"G" BdGB |"C" =cgec"G" BdGB |1"Am" =cBAG"D" F2 d^c :|2"Am" =cBAG"D" F3 G |:"D" ADFD ADFD | 
"G" BDGD BDGD |"Am" =ceBd ABGA |"D" FGEF D2 FG |"D" ADFD ADFD |"G" BDGD BDGD |"C" =cgec"G" BdGB |1 
"Am" =cBAG"D" F2 FG :|2"Am" =cBAG"D" FAd^c |]  