Erastus B. Tyler was born on April 24, 1822. He graduated from Granville College (Granville, Ohio; now Denison University) and entered the fur business until the onset of the Civil War.
He helped raise the 7th Ohio Volunteers and was elected their colonel over James A. Garfield (the 20th President of the United States). On May 14, 1862, Tyler was commissioned as a Brigadier General. He was assigned to a number of units in his career and was wounded at the First Battle of Fredericksburg (December 13, 1862).
Soon after the battle of Chancellorsville (May 1-3, 1863) his command was mustered out after fulfilling their term of service. Therefore, Tyler was transferred to the defenses of Baltimore, Maryland on June 30, 1863. He remained at or near Baltimore until the end of the war performing various duties.
During the Battle of Monocacy, Tyler commanded two regiments of inexperienced 100-days men that successfully held off numerous Confederate attempts to capture the Jug Bridge on the Baltimore Pike. The bridge was of great strategic importance as it protected the Union's extreme right flank. It was also the route used by the Union army in their retreat toward Baltimore.
Before Tyler was mustered out of service in August 1865, he was brevetted Major General in March 1865. He died on January 9, 1891 and is buried in Greenmount Cemetery in Baltimore, Maryland.