What happened in and to moral philosophy in the twentieth century?

Alasdair Chalmers MacIntyre (born 12 January 1929) is a Scottish philosopher, primarily known for his contribution to moral and political philosophy, but also known for his work in history of philosophy and theology. MacIntyre's After Virtue (1981) is widely recognised as one of the most important works of Anglophone moral and political philosophy in the 20th century. He is senior research fellow at the Centre for Contemporary Aristotelian Studies in Ethics and Politics (CASEP) at London Metropolitan University, Emeritus Professor of Philosophy at the University of Notre Dame, and Permanent Senior Distinguished Research Fellow at the Notre Dame Center for Ethics and Culture. During his lengthy academic career, he also taught at Brandeis University, Duke University, Vanderbilt University, and Boston University. Source: [Alasdair MacIntyre]( on Wikipedia