What happened in the hours leading to the announcement of martial law 40 years ago? The Palace recounts blow by blow

MASS ARRESTS. Martial law led to the arrest of Marcos critics. Photo courtesy of Dr Ferdinand Llanes, from the exhibit of UP Likas
MANILA, Philippines – While on paper, the late dictator Ferdinand Marcos declared martial law on September 21, 1972, he actually announced this to the nation on September 23.
In an essay, the Presidential Communications Development and Strategic Planning Office (PCDSPO) clarified that the anniversary of martial law is on September 23, not September 21, as popularly believed. The PCDSPO said democracy “was still functioning” on September 21, 1972, with the late Senator Benigno Aquino Jr having managed to deliver his final privilege speech at the Senate. (Read the PCDSPO’s piece through this link.)
What happened in the hours leading to 7:15 pm on September 23, when Marcos announced martial law 40 years ago? The PCDSPO and Communications Undersecretary Manolo Quezon III are tweeting events as they happened in 1972, which Rappler, in turn, is publishing blow by blow in a live blog.