The sentence is ambiguous, however, West Point was founded in 1802.

Ah, I see. The fragment in 1828 should not have been put at the end of the sentence.

> […] by cadets in 1828.

Cadets would not have founded West Point, so the sentence already switched to the context of what those cadets did (in 1828).

Right. I would have written it this way:

Academy officials determined the capsule was placed in the base of the Kosciuszko monument by cadets in 1828, 26 years after the academy’s founding.

The article also references the class of 1822, and the Roman numerals in the Academy's arms in the upper left of the page read 1802. With these three things taken together, it's hard to be sympathetic to the "founded in 1828" inferences.

English is not my native language, so I initially misread it as being founded by cadets in 1828. That seemed strange to me, so I had to read the sentence again before I figured out the actual meaning.

I wouldn’t feel too bad about it. I am a native English speaker and was confused too. It’s just a poorly-written sentence.

English is my native language, and your reading is correct. It's badly written. English is not a high-context language; you shouldn't have to know that the university was not founded by cadets for the sentence to be clear, so the "26 years after the academy's founding" part should have been a subordinate clause, separated by a comma.

Just to add to this: It's my observation as a layman (not a linguist) that over the past half-century, commas seem to have gone out of vogue for some strange reason, so a lot of contemporary English writing has become much more difficult to parse as a result. This line we're discussing here is a great example of this.

It is mine, and that's the most natural reading IMO, it's poorly written.

I would have said:

> [...] base of the monument by cadets in 1828, 26 years after the academy's founding.