Jack Dorsey on Tuesday said that both companies he heads -- Twitter and Square -- are making "Juneteenth" a holiday for employees in commemoration of the end of slavery in the US.
The holiday set for each June 19 marks the day in 1865 when Union soldiers landed in Texas with the message that the Civil War was over and slavery ended, according to a Juneteenth.com website linked to by Dorsey.
President Abraham Lincoln more than two years earlier had issued the Emancipation Proclamation, which went into effect at the start of 1863.
The arrival of Union troops in Texas provided needed strength to overcome resistance there to freeing slaves, according to Juneteenth.com.
"Both Twitter and Square are making #Juneteenth [June 19th] a company holiday in the US, forevermore," Dorsey said in a tweet.
"A day for celebration, education, and connection."
He added in a follow-up tweet that Twitter and Square will work to make company holidays of days celebrating emancipation in other countries where it operates.