Proteins are essential building blocks of all living cells; indeed, life can be viewed as resulting substantially from the chemical activity of proteins. Because of their importance, it is hardly surprising that ancestors for most proteins observed today were already present at the time of the 'last common ancestor', a primordial organism from which all life on Earth is descended. How did the first proteins arise? How does their sequence of amino acids enable their chemical activity? These questions are at the center of our scientific efforts at our Department of Protein Evolution.