I tried to make people imagine the time by looking at the scenes.

Just to make clear

The character remembers a scene in a war while looking at a musket and that suggests something after 1500s

but the character also sees for the first time in a project the name "piano" that was invented around 1710s

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there is also the telescope, that was invented around 1610s

The time is between 1550 and 1610 when we compare the fictional world to the real world

Another good way to analyse is by remembering the cities.

In our timeline the cities grew to flourish around 1300s and continued to prosper until today

It was also uncommon to have big cities in medieval time and that makes me imagine something after 1400s

Anyways,

Thanks for the comments and support

It makes me really happy

I will try to show things more detailed and clearer for you