Here is the second sentence of Lovecraft's "The Shunned House":
Sometimes it enters directly into the composition of the events, while sometimes it relates only to their fortuitous position among persons and places.
According to the English language rules, was the word 'events' representing a class of objects or why is "the" placed before it?
The definite article locates the noun it defines within the discourse context, so any question about use the definite article must take context into account. Here are the first two sentences of Lovecraft's story:
From even the greatest of horrors irony is seldom absent. Sometimes it enters directly into the composition of the events, while sometimes it relates only to their fortuitous position among persons and places.
It is clear that the events are those which are previously referred to as the greatest of horrors.
A definite article is used because "events" is referring to a specific set of things that happened. Without further context, I couldn't say what those things are. Presumably the book details a specific set of happenings, and "it" is becoming involved in those specific happenings.
Consider this sentence from the introduction of the book The Airship ROMA Disaster in Hampton Roads (by Nancy E. Sheppard), a book detailing the crash of the airship Roma:
The events you're about to read have been collected through extensive research from personal letters, essays, articles, official testimony, interviews, imagery, genealogy and notations from archives and libraries.
In this case, the sentence refers specifically to what happened regarding the crash of the airship.
In this story, "events" most likely refers to "the (set of) events (that I'm now going to tell you about)", where "events" means "the things that happen in this story". This is why the definite article is appropriate, because it refers to a specific series of events, and not events in general.
You will find, though, that Lovecraft's writing can seem old-fashioned by modern standards and there may be many grammatical features that don't follow the rules of your textbook. If you wish, take note of these as artifacts of older English and not necessarily patterns you should use in your own writing.
