All 4 Uses

although
in
Incidents in the Life of a Slave Girl
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Of the two, I preferred his stormy moods, although they left me trembling.†
Chpt 5

although = even though -- used to connect contrasting ideas
Then, although my grandmother was all in all to me, I feared her as well as loved her.†
Chpt 5
Although your masters may not find you out, God sees you; and he will punish you.†
Chpt 13
If you were purchased by your grandmother, it is doubtful whether you would be permitted to remain, although it would be lawful for you to do so.†
Chpt 34 *

Definitions:

(1) (although)
even though -- used to introduce an idea that contrasts with or makes the main statement surprising

At the start of a sentence, although can play a role similar to words like however, yet, still, even so, on the other hand, or nonetheless—all of which signal contrast. In the middle of a sentence, although can sometimes be used where but or though might also work, but though or but often sound more natural. For example, "She's a great teacher, though not the most popular" is usually smoother than "She's a great teacher, although not the most popular."
(2) (meaning too rare to warrant focus)