T(h) 12 I 2 o 4 E 20 N 14 L 1 P(t) 12 I 51 n(S) 5**
r 85 E 20 s 91
6 L 3 P 7 r
y 1(5) d 81
19 O 9 i 19
91(4) C 5 o 14 C 7 T 9 N 2(0) O 51 s 85 i 3 y**
z 81 d 4 n 6 z

The numbers seem to act like ends of wormholes, taking you from the letter(s) preceding a number to the letter(s) following the identical number.  I worked from both ends and met in the middle.  The solution, to the best I could determine is:

This encryptions old description only.

I had a little trouble deciding what to do when two numbers appeared next to each other, and I didn't end up needing either "z" that appeared in the text, so something might be missing.