Develop a musical composition by integrating the alphabetically represented musical pattern and the supplied melodic theme.
X:1
L:1/8
Q:1/2=100
M:2/2
K:Bb
['dedc BGGB', 'B c Bdfd bagf gbfd cBcd Bdfd']  
X:1
L:1/8
Q:1/2=100
M:2/2
K:Bb
 B/c/ | dedc BGGB | FGBc defe | dedc BGGB | FBAc B/B/B B :| c | Bdfd bagf | gbfd cBcd | 
 Bdfd Tf=efd | gfdf gabg | fdbg fdBd | cBdc BGGB | FGBc defe | dBcA B/B/B B |]  