To prove the p-adic Hodge-Tate decomposition, Fontaine interpreted C_p(1) as the rational Tate module for the p-divisible group (in the classical sense!) of O_K-differentials of O_{Kbar} for the maximal unramified extension K of a p-adic field. In this talk, we will show this calculation. Speaker(s): Kannappan Sampath (UM)