### Period Relations for Automorphic L-functions

Abstract: Euler's solution to the Basel problem $\zeta(2)=\frac{\pi^2}{6}$ was the first instance of a special value formula. In the 1970ies Pierre Deligne unified certain results and expectations about special values of automorphic L-functions in a precise conjecture. After a quick introduction to Deligne's Conjecture, I will present recent results on the automorphic side which confirm predictions of Deligne in higher rank situations when supposing the existence of the associated motives.