Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
Q:1/4=120
M:4/4
K:D
['a2 c>gTg>f ecc>e', 'F>GA>a b>ag>f{f} e>ad/{d} ^cB/A/ (B/A/d/c/ B/A/G/F/) G/F/E/D/{^G}']  
X:1
L:1/8
Q:1/4=120
M:4/4
K:D
"^Solemnly slow" A |{de}!p! f2 Te>d d>A{A}"_>" a2 | c>gTg>f ecc>e | 
{de} f2 e>d dA{A}"_>" !fermata!a2 |"^Exp."{gf} eba>^c d2- dz/A/ |{de} f2 Te>d d>A{A} a2 | 
 c>gTg>f ecc>e | !fermata!f>e{e}d>c (B/A/d/c/ B/A/G/F/) | EBA>^C D2 D |] E |!f! F>GA>G F>GA<f | 
 B>AG>F{F} EA/E/{C} ^CB,/A,/ | F>GA>=B c>_B!p!Af |"^Exp." eba>^c d3 z/ E/ |!f! F>G{FA}A>G F>GA>a | 
 b>ag>f{f} e>ad/{d} ^cB/A/ | !fermata!f>"^dim."ed>c (B/A/d/c/ B/A/G/F/) | G/F/E/D/{^G} A^C D2 D |]  