Totally random question here:

In 15th century England, the king's personal guard would wear what type of armor around the palace while on duty?

some kings in france seemed to have had scots as their guards. In the pictures I know of they are in brigandines. I do not know if there was a big difference between being in battle and at home for guards though, you were paid to be a soldier still even if off the field. Interesting thought.

RPM

The 16th-century Beefeaters didn't seem to have worn armor on guard duty, although it is not impossible that they might have worn a mail haubergeon beneath their doublets in the same way that many 16th- and 17th-century English gentlemen did when they were expecting trouble.

For what it's worth, these fellows are gaurds of a church official, ca. 1495:

http://www.myArmoury.com/talk/download.php?id=10729

No full plate, no helmets. Note jack chains on arms/lower legs of foreground figure. No jack or breast on the fellow in background, just a hauberk(?). Could be that the kneeling figure is an officer of the guard, thus more richly armoured. All the guards depicted in this painting are armed with vouges francais.

Not just for guards but I wonder how often knights, men-at-arms or common soldiers would " arm down " i.e. wear partial armour when the immediate threat level was low but having some " comfortable " defences for long hours of wear was required by the " job " or just prudent ?

I can see light helmets, maille shirts or jacks and limited arm defences like jackchains or splinted bracers ? Oh, a buckler being more offensive and sort of a minimum defence. This " semi-off-duty kit " would vary a great deal depending on period looked at.

There is a tendency with full plate armour to imagine an all or nothing usage ? Full plate might be used only for formal battles, for display, or sports use ( Jousting. ) Chevauché and on the march or body guard service might mean more selective amounts of coverage.

Hope this is only a little bit off topic and related to the original question is about 15th century England guard duty.

I have seen in inventories listings for brigandines that seem specialized for light use. I think in italy they were quite popular.

There are many pictures of the scot guard in brigs' sallet, arm armour and pole weapons. There also are the sleeping guard pictures which are very common and usually very well armourer. It likely depends on what then have going on in the area,probable danger.

RPM

There is an Italian source, the biography of one of the better artists, that talks about his time in service. The writer has completed a day's duty and retires to his rooms to eat and get dressed up for the night. He removes his armour that he has worn for the day's duty and redresses himself in a smarter, fancier armour for posing in!

Not quite the same thing but interesting enough to comment on. I'll have to emptya few boxes out and hunt for the book in question!

Try to check up some accounts of the chevauchees in the Hundred Years' war. I seem to recall some direct statements to the effect that the knights and mounted men-at-arms had taken off part of their armor to work better in the mobile environment of such raids. Of course, they still had the rest of the armor carried on carts or pack animals to prepare for cases where they might have to fight a full-scale battle, especially to defend themselves from angry locals and pursuers.