In the shadow of night, I see the full moon rise, telling me what’s in store…
                                                                                                — Whitesnake, “Still of the Night”

Being creatures of the modern world, it can be difficult to get into a medieval mindset for our fantasy medieval/renaissance RPG campaigns. Things we take for granted, such as a wide variety of food, a robust nightlife, and indoor heat (absent numerous fireplaces), work their way into our ostensibly medieval settings, often without anyone around the table realizing it.

Of course, indulging in the “fantasy” aspect solves a lot of these problems. Maybe medieval France didn’t have potatoes, but that’s not to say your Western Europe-inspired setting doesn’t have them. Similarly, a city with wide magic may have light globes or enchanted ceiling panels that enable buildings and streets to be adequately lit at night. And maybe your fantasy medieval town watch does act like a modern police force with a dedicated investigative division.

A few months back, in the waning days of 2023, I found myself researching something on the internet when I came across the idea of biphasic Sleep. After falling into that rabbit hole for a bit, I decided to incorporate biphasic sleep into my campaign.

What is Biphasic Sleep?

Without going into a lot of scientific jargon that I’d probably be misusing anyway, biphasic sleep is a sleeping pattern where you sleep during two parts of your day. In our modern world, this typically manifests as a normal night’s sleep and a daytime nap (or siesta).

In the past, however, it is thought that, with artificial light being expensive or, in the case of tallow candles, too smelly, most people went to bed with the sunset and rose at dawn. This is a pretty long period, especially in winter months, so people would generally sleep for a few hours, get up in the middle of the night for an hour or two, and then go back to sleep for another few hours until dawn.

This hour or so in the middle was rarely spent staring at the ceiling. People would get up, have a snack, hit the outhouse, do chores (anything that could be performed in the moonlight), say prayers, or, in the case of romantic partners, put on the Barry White album (you know what I mean!).

Once artificial light became more ubiquitous, sleeping schedules shrank as people could stay up longer and wake up earlier. The reduction in sleep time meant that more people, most people, would simply sleep straight through or, if they did wake up, try to get back to sleep as quickly as possible.

Is this actually true? Maybe, maybe not, but it still gave me food for thought!

Thanks for the Lecture, but What Does This Mean for RPGs?

Most roleplaying games assume that player characters must rest for 8 hours or bad things start to happen, whether that be some form of exhaustion check or penalties to actions. I’ve never read a rulebook for a game set in a pre-industrial period that suggested that an 8-hour sleep, or “long rest” in modern Dungeons & Dragons parlance, can be split into two sleep periods with a semi-active period in between.

Having said that, I know that you can easily read biphasic sleep into the long rest, as the definition includes light activity and 2-hour watch periods, but I’ve never played or run in a game where the whole party made a ritual out of getting up in the middle of the night together. It just seems weird because that isn’t how we sleep today.

For me, the idea of biphasic sleep fits comfortably into my OSR campaign, especially considering that the chief lawful deity, Valtar, is represented by the moon. It makes sense that Valtar’s worshippers would pray to him at midnight when the moon is at its highest (my campaign world is Earth-like, with one sun and moon).

Note that, in my campaigns, both OSR and modern, I usually ignore the rule that an interrupted night’s rest prohibits healing or spell memorization, as these only serve to slow the game down. If the group is camped, and they can’t heal or refresh their spells because a couple of hobgoblins wandered into camp and caused trouble, then they’ll probably just stay camped for another night.

So how does implementing biphasic sleep impact my campaign?

Time Matters

Ordinarily, at the end of the game day, my group builds a camp, eats supper, and then hopefully gets a good night’s sleep. During the night, they set watches, but everyone is stuck with the resources they have left as they don’t replenish until morning.

In my campaign, I’ve divided the night into 5 phases. There are two “watches” of about 2 hours each, followed by a 1-hour or so period when everyone is up eating, praying, and studying, followed by another two “watches” before daybreak.

As I’ve ruled that the morning 4-hour “snooze” followed by an evening snooze replenishes everyone at midnight, then when a night encounter takes place matters a lot more. Player characters have diminished resources when facing monsters during the early part of the night, but they’re at full power in the pre-dawn hours. Unfortunately, that also means that the resources they spend in pre-dawn conflicts affect them for the rest of the day.

Even if you want to keep resting as-is, biphasic sleep offers opportunities for roleplay. Wandering NPCs may wait to approach a camp until midnight, and there is always at least part of a night when everyone is up and alert, rather than just the watchers.

Magical Adjustment

Having the player characters refresh at midnight comes with a few adjustments. For example, when in dangerous territory, characters may choose to consume rations rather than cook and risk having a campfire attract danger (unless, of course, the bitter cold is a greater enemy).

Light sources are another problem. One of the reasons for biphasic sleep is the idea that candles and oil are precious and that no one wants to waste them but sleeping for 10-12 hours every night is not practical (although it sounds like paradise to me!). So, how is one expected to regain spells?

For divine casters, this isn’t a problem, as they are usually encouraged to either use rote prayers or speak to their deity directly; the powers that be don’t usually require precise readings that haven’t been committed to memory over time.

Arcane casters are another matter. If you’re playing any flavor of D&D, then arcane casters “fire-and-forget,” requiring study after a good night’s sleep. (In my current campaign, arcane casters don’t so much forget as they need to study astrological charts and fluctuating ley lines to ensure that their spellcasting is effective on any given day).

My solution was to take the need for sight away. In my campaign, arcane script is a semi-magical type of braille. Any arcane caster that runs their fingers over the script can both read the symbols and decode the magical meaning and power within them (so a non-arcane caster can learn to read “Xanish” (my deity of magic is Xanadu), but they still can’t cast it or otherwise access the magical properties).

Midnight Services

As I mentioned above, Valtar is a lunar deity, so it makes sense that my campaign follows the more modern convention of having a day begin at midnight, as opposed to sunrise, sunset, or any other norm. Also, given Valtar’s status, midnight is considered the time when worshipers can best connect with their deities, so most of the powers in my campaign encourage midnight prayers and worship regardless of alignment.

That means that, within a community, it wouldn’t be uncommon for everyone to get up in the middle of the night and attend services. At this hour, the temples would likely be the only buildings in the community fully illuminated (although some may worship privately or even in secret, depending on their deity).

If the community is generally lawful, then everyone would be expected to attend, with innkeepers rousing their guests to make sure they get to the temple on time (and, more importantly, ensure that they don’t remain to rob the inn blind!). Town watches are empowered to skip services to patrol and any crimes committed during this time are harshly punished (also, while it goes unsaid, watchmen are encouraged to root out secret chaotic meetings during this time, so such services are usually well-hidden and constantly changing as to actual time and place).

 Wrapping Up

As I hope you’ve noticed by now, introducing biphasic sleep has had a profound effect on my campaign world. Sleep patterns change, time of night matters, arcane script is affected, and even the daily calendar is a bit different. I also hope that I’ve encouraged you to give it a try. It may or may not be more authentically medieval, but it will certainly help make it seem a bit more fantastic.

Have you tried using biphasic sleep or another alternative to the traditional “sleep for 8 hours, then prep and breakfast?” Let us know in the comments!