St Mark
Today is the feast of St Mark, the writer of the shortest of the four Gospels, and you can find the readings for the feast at Matins here. St Mark was, according to the martyrology, the 'disciple and interpreter of the apostle St. Peter'.
The entry for today goes on to say that:
he wrote his gospel at the request of the faithful at Rome, and taking it with him, proceeded to Egypt and founded a church at Alexandria, where he was the first to preach Christ. Afterwards, being arrested for the faith, he was bound, dragged over stones, and endured great afflictions. Finally he was confined to prison, where, being comforted by the visit of an angel, and even by an apparition of our Lord himself, he was called to the heavenly kingdom in the eighth year of the reign of Nero.The Greater Litanies
This is also the day on which the Litany of the saints is traditionally sung as part of a procession at Mass. It can also be said privately after Lauds, and those who are bound to say the office (ie clergy and religious) are required either to participate in a procession or say the Litany privately.
ANZAC Day
In Australia and New Zealand, it is however, ANZAC Day, the anniversary of one of the most horrendous defeats of World War I, at Gallipoli in 2015, but a defeat that bought forth a new sense of nationhood in those countries. In the older calendar, there is a special indult allowing the Mass of the day to be replaced with a requiem for the souls of those killed in war; in the newer calendar, the day actually has its own propers, and St Mark is transferred to tomorrow.
So if you would, please remember to say a prayer for the repose of the souls of those who served in war.