Eli5 How did classical music composers memorize their songs back then after creating them?

Question

Let’s take for example the nocturnes of Chopin.

My preferred one is nocturne n. 20

He certainly didn’t have studio machine to record their sound AFAIK

How then did he memorize and write down everything to remember later?

Did he start playing the piano, write down the notes, continue playing or did he memorize the whole song by heart without any writing process?

Sorry 4 my bad English btw. Not a English native speaker.

EDIT : thanks everyone for the explanation.

In: 157

Answer 1

Some composers have a complete idea in their head and can simply score it out without an instrument. It was said that Mozart had that level of recall. Others have to have an instrument handy and make many many corrections as the go — Beethoven was famous for this even as he was going deaf.

Most composers work within a style or an idiom — an approach to melody, harmony, rhythm, and tempo that they would follow through a piece. For example, Bach and his contemporaries wrote fugues — there were very specific approaches to fugue called the form of the piece (number of measures of a particular theme, repetition of theme, variation of theme, and length of each). Most of the great music that was written up until the Romantic period in the mind 19th century was based on other music in a specific form. When a contemporary musician plays a 16 bar blues, they are not inventing a new style or form, they are just working within an idiom that is well understood. Even in the Romantic Period composers like Chopin and Dvorak celebrated dance forms from their home countries — mazurkas, polonaises, polkas, souzedskas and so forth. They were usually not writing from scratch, but starting with a template and creating new ideas to fill in. This whole process makes scoring music a lot easier — the composer, copyist, musician do not have to carefully watch each note, they can use their training and experience to anticipate when things repeat, how often to play a part, when to play close attention and when to relax.

That said, modern orchestral composers often use technology as an aid and break a lot of forms and invent new styles all the time.

HTH