While the first analysis of the gambit appeared in 1825 and was published in Barcelona, the New Orleans player Otto Tennison was instrumental in popularizing it. When he first published his analysis in 1891, he called it the Black Rook’s Gambit. Today it's known as the Tennison Gambit and it begins with the moves 1.Nf3 d5 2.e4.
Otto Mandrup Tennison was born in Copenhagen on December 8, 1834 and at the age of 20 graduated from Heidelberg University in Germany with a degree in engineering. He then moved to Richmond, Virginia where he was employed as a surveyor. The year 1854 found him in Kansas Territory surveying the area around the city of Leavenworth.
Tennison served with the Union forces in the US Civil War as Lieutenant Colonel in the 1st Kansas Infantry Regiment and after the war in the 1890s he was living in New Orleans when he published his analysis on the gambit.
In May, 1863, Tennison decided he could no longer support the Union cause and resigned his commission. As a result he was to face a court martial but managed to escape to a Confederate camp in Kentucky. He was not allowed to join the Confederate Army and was instead taken as prisoner and held captive for 16 months.
Thinking he was a Union spy, the Confederates had sentenced him to hang. Ultimately his sentence was reprieved when the Confederates were finally convinced he was not a spy. They then gave him the rank of Captain in June, 1863. Nearly a year later he was later wounded at the Battle of Pleasant Hill and served out the rest of the war as a drill master before leaving the army in June, 1865 and moving to New Orleans where he worked as a civilian in the commissary.
In 1873 in New Orleans, Tennison was involved in an armed insurrection against the New Orleans Reconstruction government and over the several years he was involved in other military commands and participated in the Louisiana Militia, the Continental Guards, the German Battalion, the Orleans Light Infantry, and the Louisiana National Guard, in which his unit was known as the “Tennison Rifles.”
In the 1880 Tennison was a charter member of the New Orleans Chess, Checker, and Whist Club and from the 1880s through the 1890s served as a reporter for the Republican newspaper and was a court reporter at the House of Representatives of the State of Louisiana.
I also discovered that a US Patent (577433) was granted to one Charles B. De Lamarre in 1897 for a door alarm that was assigned to Tennison, but was unable to discover what, if anything, Tennison did with it. The alarm consisted of a bellows attached to a "whistle pipe." My feeling is that this alarm was probably less successful than his gambit...the gambit is still around, but you can't find the alarm anymore.
He died in the Confederate Soldiers’ Home in New Orleans on June 10, 1909 at the age of 74.