The blue of a royal family
Savoy blue, also called savoy azure, is named after the House of Savoy. This family ruled Italy as kings from 1861 to 1946. Blue was the color of the family, and it became a national color when Italy was united in 1861.
Italy became a republic in 1946, but the color stayed. People started calling it Italian blue. Officers in the armed forces still wear a blue sash, and the president's flag has a blue border.
Why Italian teams wear blue
Italy's flag is green, white and red, yet its national sports teams play in blue shirts. That blue comes from the House of Savoy. The football team is known as the Azzurri, which means "the blues" in Italian.
About the code
The code #4B61D1 matches the one in the Wikipedia section on savoy blue. One catch: the web page Wikipedia cites as the source for the code is about a different color, ruddy blue. So the code is not backed by a solid source. Real Italian team shirts vary from year to year and are often lighter.
White text on savoy blue has a contrast ratio of 5.34 to 1, which passes for normal text. Savoy blue buttons with white labels should read well, and the contrast checker can confirm a pair. Savoy blue sits between Persian blue and periwinkle.

