The phrase "although it was regarded" is correct and usable in written English.
It can be used to introduce a contrast or exception regarding how something is perceived or considered.
Example: "Although it was regarded as a failure by some, the project ultimately led to significant advancements in technology."
Alternatives: "even though it was seen" or "despite being viewed".
With respect to the particular quantum theory of Bohr and Sommerfeld, however, it wasn't crucial, although it was regarded as such at the time, because that theory predicted no splitting for a beam of silver atoms in the ground state \((L = 0)\).
She began to put her own ideas to paper at a very early age, and although it was regarded as unseemly at the time for a woman to be publicly intellectual, she was able to be an intellectual in private in regular conversations with her middle-brother John.
Although it is regarded a classic, readers point out that the supposingly big and tough facist rulers don't last very long, or as Insolito so-correctly puts it, "the regime itself seems particularly brittle".
It's not something symbolic or allegorical (although it is regarded as ultimately mysterious).
That is, the conscience of even a persecutor must be respected, such that although it is regarded as mistaken, the individual should not be forced or even bribed to act against it.
Although it is regarded as a best practise to favor immutable data structures over mutable ones [4], imperative code is typically full of reassignment operations since these provide a convenient way to update fields in complex data structures.
Although it is regarded as the gold standard [ 2, 3], autologous bone grafting can cause complications such as morbidity and infection; moreover, only limited amounts of autograft material are available and the harvesting process involves additional trauma [ 1, 4], producing an unsatisfactory outcome [ 5].
Although recognised, it was regarded as " a European word", and was more commonly used by the younger participants.
atlanticum has been established to be native, although for many years it was regarded as an alien species.
FP No.1 could be very unpleasant depending on the weather, was abhorred by some as barbaric, and in some units was ritualised (e.g. by locking a man in a shed and throwing the handcuffs in with him); there were also cases of Australian troops releasing British troops whom they found tied up, although in other units it was regarded as a necessary sanction for serious offences.
This strategy combined assault by land and air to ensure rapid progress; although in reality little was new, it was regarded as a revolutionary form of warfare.
