John Albion Andrew served as governor of Massachusetts throughout the Civil War, holding the office from January 1861 through January 1866.  Born in Windham, Maine, he attended Bowdoin College and later became a lawyer, settling in Boston.  He was elected as a Representative to the General Court in 1858 and  won the 1860 gubernatorial election with the largest margin of the popular vote to date in Massachusetts.  After his election, he traveled to Washington, D.C. and while in the Capitol, was able to speak with representatives from both Southern and Northern states about their political views.  During this visit he came to the conclusion that a civil war  was inevitable.

After his inauguration, Andrew started making preparations for war.  He began with the idea to quietly ready forces while avoiding any direct means of instigating a conflict and panic among the people.  Andrew made his preparations public with General Order number four, issued on 16 January 1861, commanding militia officers to update their rosters and replace men who were no longer able to serve in active duty with eligible fighting men and to fill any vacancies.  He urged his fellow governors of New England to start military preparations as well. 

In this letter, Andrew writes to General Winfield Scott, the general-in-chief of the United States Army, for advice and information on how to best prepare the state militia for battle and to inform Scott and, by extension the federal government, that Massachusetts would be ready to assist the Union wherever and whenever the need arose.  Andrew was the first governor to make this offer and Massachusetts was among the first to respond to President Abraham Lincoln’s call for troops after the attack on Fort Sumter on 12 April 1861.