The phrase "as long thought" is correct and usable in written English.
It can be used to indicate that something has been believed or assumed for a significant period of time.
Example: "The theory was confirmed to be accurate, as long thought by many scientists."
Alternatives: "as previously believed" or "as long assumed".
Gut bacteria were found to have a surprising role in disease 20 years ago, when Australian scientists showed that stomach ulcers aren't caused by stress, as long thought, but by chronic infection with the stomach bacterium Helicobacter pylori.
Hummingbird tongues are tiny pumps that suck up nectar not merely passive strawlike structures as long thought, new research suggests.
And there are tantalizing clues that the innate system itself, instead of mounting a single generalized response as long thought, may have specific pathways to target particular pathogens.
That finding led him to conclude that rice was first domesticated in China, not Southeast Asia as was long thought.
The expulsion of the Jews in 1492 did not signify the end of Jewish influence on Spanish history, as was long thought.
For as long as the thought lasted, that snatched possession felt to Christine like the only thing worth living for: a possibility of joy that was no longer available to the mothers of these children.
(Whether because of faulty early metronomes, as was long thought, or because of the misreading of the composer's intentions over the years, those markings in many cases indicate tempos faster than those we are used to).
The Incas fashioned gorgeous gold, silver, and copper statuettes and ornaments, but they shouldn't get credit for introducing "industrial scale" metallurgy in South America, as researchers long thought.
We also risk returning to health problems of decades ago as illnesses long thought wiped out come back.
"Thinking is ok," one British journalist quipped on Twitter, "as long as your thoughts are in line with a set of rules we make up as we go along".
I now know that the "worse" my meditation session is, in terms of my mind getting distracted by thought, as long as I notice myself thinking, and gently guide myself back to breath, the better practice I'm getting.
