On the morrow is an archaic expression, alluding to immediate action on the next morning.
It is often interchanged and mixed up with “in the morrow”, which has a slightly different meaning, referring to the entire duration of the next morning.
Both expressions are archaic and out of fashion, similar to the greeting Top of the Morning to You, however, the latter at least sees some use in contemporary contexts, while the titular phrase and its variant are completely outdated and forgotten, save for a few sporadic uses here and there.
Although it is not known, where exactly the phrase “On the morrow” originated from, the term “morrow”, in its current developed by the end of the 14th century.
The first written case of the phrase “On the morrow” can be found in Charles Knight’s Popular History of England, which was published in 1547.
The other variant of the phrase, “in the morrow” first appeared in print in 1574.
“On the morrow” grew in popularity in the modern age, with the growth of the British empire, spreading to the Americas as well as the Asian colonies.
It reached its peak in the 19th century, where it would appear in all sorts of contexts, ranging from theater plays, literary works of art – both novels and poems – as well as everyday conversations.
By the 20th century, however, its sun – similar to that of the British empire – began settling, rendering the expression archaic and out of fashion, appearing solely in historical drama or motion pictures.
Its popularity experienced a slight upheaval in the 2010’s, as it was used in a tweet by @Warnerbro, and a short film with the title “On the Morrow” premiered in October 2014.