This document provides a timeline of middleware evolution from 1999 to present. It begins with Purdue University Network Computing Hubs (PUNCH) in 1999 and covers early grid middleware like the Globus Toolkit. It then discusses virtualization research like InVIGO and Nimbus. Major cloud computing platforms like Amazon Web Services, Eucalyptus, OpenStack, and CloudStack are noted from 2008-2012. The author discusses deploying infrastructure as a service on the Open Science Grid and using OpenFlow for dynamic networking. In conclusion, the author argues that virtualization has matured and clouds fulfill the vision of grids by providing on-demand, elastic resources and data access.