Summer season = medieval week and a for medieval week I really need a bag for my German dress. Looking at a lot of pictures I saw a model that seemed to be used by both males and females and also used in a very varied social status.
And as I work this way: see pretty thing, make pretty thing. I just had to make myself a bag and as I like to share I also made a pattern diagram.

But first, the finished bag.

16th century German - bag
It is made in Swedish bark tanned reindeer, the lid and strap is in 3mm vegetable tanned cowhide and the red is chrome tanned goat. I usually try to stay away from the chrome tanned leather because of the chrome, but this red is just so beautiful that I can’t stop myself.

16th century German - bag back
As you can’t really make out the backside of the bags from pictures you have to make something up. I decided to use the same shape as on the lid, as that makes it both a bit sturdy, gives me something to put a inner pocket on and it looks pretty. Also when cutting leather I find that you get the most useful scrap pieces if you try to keep your work in rectangles that you then cut down. For example, the things I cut away on the lid and strap can easy be used as other straps or perhaps a bracelet.
Here you can clearly see the seam that fasten the inner pocket. The inner pocket is a modern convenience things, for a more period correct bag you should probably leave it out

16th century German - bag - lid
A close up on the lid. The button is made with a wooden core that have been covered in leather.

16th century German - bag - strap
16th century German - bag -  side strap
Something that I have not done yet is to sew the strap closed, so that you can open the bag without it slipping of your belt.

16th century German - bag - with open lid
When you open the lid you can see that it has two external pockets and a drawstring to keep it shut.

16th century German - bag - button
The button is fastened in the front piece of the bag.

16th century German - bag - button
To make sure that the button stays on, the leather that is used to cover the button is the leather that becomes the piece that is sewn on to the front piece of the bag. I also used extra long threads that I wrapped around the neck of the button to make it more secure and long lasting.

16th century German - bag - inner pocket
On the inside there is a pocket, I have no historical sources for this, but a bag needs its bag for “girl stuff”. I first sew it onto the back piece, through both lid/strap and the back piece and then sew the seams on the sides, the seams that form the pocket. Before sewing it on I also put some water on the front bit of the inner pocket, and stretched it a bit just at the front piece, this makes it easier to put stuff into the pocket, and you can see how it is slightly looser on the picture

16th century German - bag - pockets
Here we have the pockets, the pattern piece is sewn on so that it forms a pouch, my leather is a bit thick so it does not drape as well as it should, but it will become softer with use.

16th century German - bag - pocket detail
The drawstring on these pockets are well thought out, pull it open easy.

16th century German - bag - opening pocket
Put stuff inside.

16th century German - bag - closing pocket
And then pull on the long ends to shut it again.

And now on to the pattern.
The + marks where you should punch a hole, this is most practical to do just after cutting out your leather before any sewing is done. Except at the centre back were the holes should be through bot lid/strap and back piece and therefore is better to punch after you sew it on.
The dotted lines are your sewing lines, where your seams should be or where you should place your other pieces. I use a needle and punch tiny holes through the paper pattern to mark these lines.
The pockets have no seam lines as there is such a small (2mm) seam allowance, and on the front piece the dotted lines is how you should put the pocket pieces to form pouches.

16th century German - bag - overwiew

16th century German - bag - front and back
16th century German - bag - strap
16th century German - bag - pockets
16th century German - bag - inner pocket

And so, some inspirational picture as well.
Amorous_Peasants
As you can see she have only one pocket, it is shaped differently at the bottom and there is tassels.

soilder and his whife
One with a smaller lid and three pockets.

bagmaker
two other variety.

inspiration
My bag is kind of the same size as this nice girl.