Schiller and Goethe aren't part of the literary period of (Early/Jena) Romanticism. Instead, they both started out in Sturm und Drang and later dived into Weimarer Klassik. However, because they both lived in/near Jena at the time and were in frequent dialogue[1] with the Romantics, it's still interesting to see how their works and philosophies influenced each other.

If you find yourself thinking "what even is Romanticism", the vibe is personal freedom and individuality, but also everything (science, nature, religion) is connected. Novalis caputures the energy pretty well in his poem Wenn nicht mehr Zahlen und Figuren:

Wenn nicht mehr Zahlen und Figuren Sind Schlüssel aller Kreaturen Wenn die, so singen oder küssen, Mehr als die Tiefgelehrten wissen, Wenn sich die Welt ins freye Leben Und in die Welt wird zurück begeben, Wenn dann sich wieder Licht und Schatten Zu ächter Klarheit werden gatten, Und man in Mährchen und Gedichten Erkennt die ewgen Weltgeschichten, Dann fliegt vor Einem geheimen Wort Das ganze verkehrte Wesen fort.

I didn't find a translation but I will edit this if I ever hunt one down or find the energy to translate it myself.

Also note that I didn't study any of this formally, I just know what my school teachers taught me and what I researched in my free time whenever I went down another "I love Friedrich Schiller" rabbit hole.

[1] In Goethe's case this means friendship, in Schiller's it means... arch-nemesis-ship? A feud? Bitter hatred? Messiest friend group of the 18th century istg