Immanuel Kant (22 April 1724 – 12 February 1804) was a German philosopher and one of the central Enlightenment thinkers.

His daily schedule then looked something like this.

He got up at 5:00 A.M. His servant Martin Lampe, who worked for him from at least 1762 until 1802, would wake him. The old soldier was under orders to be persistent, so that Kant would not sleep longer. Kant was proud that he never got up even half an hour late, even though he found it hard to get up early. It appears that during his early years, he did sleep in at times. After getting up, Kant would drink one or two cups of tea — weak tea. With that, he smoked a pipe of tobacco. The time he needed for smoking it “was devoted to meditation.” Apparently, Kant had formulated the maxim for himself that he would smoke only one pipe, but it is reported that the bowls of his pipes increased considerably in size as the years went on. He then prepared his lectures and worked on his books until 7:00. His lectures began at 7:00, and they would last until 11:00.

His academic duties discharged, Kant would go to a restaurant or a pub for lunch, his only real meal of the day. He did not limit his dining company to his fellow academics but enjoyed mixing with townspeople from a variety of backgrounds. As for the meal itself, he preferred simple fare, with the meat well done, accompanied by good wine. Lunch might go until as late as 3:00, after which Kant took his famous walk and visited his closest friend, Joseph Green. They would converse until 7:00 on weekdays (9:00 on weekends, perhaps joined by another friend). Returning home, Kant would do some more work and read before going to bed precisely at 10:00.

Sources:

• https://dailyroutines.typepad.com/daily_routines/2007/08/immanuel-kant.html
• http://meaningring.com/2015/04/17/daily-rituals-kant-by-mason-currey/