Too bad there's not more detail, but I did find this:
Chronology: Robert E. Lee Timeline
1861
March 1. Returned to Arlington to his family.
March 16. Appointed Colonel of First Cavalry.
April 16. Offered command of United States Armies.
April 20. Resigned commission in army.
April 23. Accepted command of Virginia forces.
May – July. Organized troops and advised President Davis in Richmond.
August – October. Was in charge of abortive campaign in Western Virginia.
November. Had charge of coast defense in South Carolina and Georgia.
http://www.stratfordhall.org/meet-the-lee-family/general-robert-e-lee-1807-1870/chronology/
And this: "The Provisional Congress of the Confederate States of America met for the first time in the Capitol on July 20, 1861...."