Start from creating a background ornament.
In a new document 4000x4000 pixels place the eagle in the corner (it was cut out before from the background sky and rocks)
step 2 of 12
Copy the eagle layer, move it to the right, not leaving space inbetween. Repeat this 3 times more to get a "line" of eagles. Merge together all the layers with eagles.
step 3 of 12
Repeat previous step few times to get the surface "filled" with the eagles :)
step 4 of 12
Now select the triangle, using rectangular lasso tool. The triangle should have 2 equal sides and a 90 degree angle.
step 5 of 12
Cut out the triangle, make it the only visible layer. Scale it down so it is about twice smaller than the canvas size and move it to the corner.
step 6 of 12
Copy the layer with the triangle and transform - flip vertical. Place the second triangle under the first one. Merge them together.
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Press Ctrl+Shift+T, move the center of the transform shape to the "center" (90 degree) corner of a big triangle, choose to turn the shape 90 degrees, press enter. Now you see half of the canvas covered with the ornament. Press Ctrl+Shift+Alt+T twice to repeat the last transformation and get the full square ornament.
step 8 of 12
Time to create the circle thing in the middle. Take the eagle again, place it above the ornament layer as it is shown.
step 9 of 12
Press Ctrl+Shift+T, move the center point of a transform shape to the center of the ornament. Choose to turn the shape to 45 degree, press enter.
step 10 of 12
Press Ctrl+Alt+Shift+T 6 times to repeat the previous transformation. Merge down 6 layers, forming the circle of eagles.
step 11 of 12
Now crop the image to get proper square (there was some extra canvas space on the sides). I changed the blending mode of the layer with the circle to "Darken" and resized image to 1500x1500 pixel to fit the requested size.
step 12 of 12
There is my photoshop window screenshot during the work.