A tale of two swords

Something that seems common across the the sword-wielding globe in history is the idea of the upper-class owning, if not wearing 2 swords.

The most famous example is of the Japanese samurai owning and wearing the longer katana or tachi with the shorter wakizashi to form the daisho. In this case, the samurai wore them together showing status. In this case, the katana/tachi is the main sword used mostly outdoors, backup in battle, and in duels. The wakizashi is used indoors and other tight spaces as well as a backup to the backup.

China is known for the jian and the dao. The distinction here is mostly late Han Dynasty and the Ming Dynasty as the jian all but disappeared in between and the main sword in the early Han Dynasty. The jian was the gentleman of weapons used for civilian combat and dueling. The dao was a war sword predominantly.

With the Middle East, the pairs are mostly contemporary to each other and are essentially scimitar with large dagger.

In Persia (modern Iran and Georgia), there was the qama and the shamshir. The qama was used in civilian combat as well as dueling. The shamshir was a war sword, mostly for cavalry use.

In Ottoman Turkey, there was the yataghan for civilian and the kilij for cavalry warfare.

In Afghanistan there was the Khyber knife for most contexts and the pulwar for cavalry warfare.

In Europe, particularly in the Holy Roman Empire and the British Isles, the weapon divisions are similar to the rest of these examples but with a clearer division of cut vs thrust.

During the High Middle Ages, a knight may have an arming sword for most contexts and a falchion to deal with peasants.

During the Late Middle Ages, a knight may have a thrust-oriented longsword for armored combat and a one-handed sword for everything else.

During the Renaissance, the rapier was civilian and dueling focused and the backsword or dussack/storta was meant for war.

In the Enlightenment and Napoleonic eras, the smallsword took the role of the rapier and the backsword or sabre remained mainly for war.

Even the Victorian era saw the ownership of 2 swords where many officers owned both a regulation military sword for dress regulations and a foreign sword or smallsword for combat.

With the exception of Japan, each of these regions and periods, nobles tended to own two swords for different reasons and not wear them together: one sword for one set of tasks and another for another set of tasks. Also note, these examples aren't concrete, just trends as many people had only one type of sword and a few were wealthy enough to have more.