star trek - Was Trelane really seeing Earth 900 years ago, or perhaps 600 years ago, or could he see any time period he chose?

Star Trek TOS "The Squire of Gothos":

TRELANE: I can't tell you how delighted I am to have visitors from the very planet that I've made my hobby. Yes, but according to my observations, I didn't think you capable of such voyages.

JAEGER: Notice the period, Captain. Nine hundred light years from Earth. It's what might be seen through a viewing scope if it were powerful enough.

TRELANE: Ah, yes. I've been looking in on the doings on your lively little Earth.

KIRK: Then you've been looking in on the doings nine hundred years past.

TRELANE: Oh, really? Have I made an error in time? How fallible of me. Oh, I did so want to make you feel at home. I'm quite proud of the detail.

KIRK: General Trelane.

So from the episode it clearly states that he's seeing things 900 years in the past, which is his present because he's 900 light years from earth. He also states that he's been observing in his present time earth and that he's surprised that a relatively primitive culture technologically speaking to make such a far away space journey.

Star Trek TOS "The Squire of Gothos":

TRELANE: DeSalle, did you say? Un vrai Francais?

DESALLE: My ancestry is French, yes.

TRELANE: Ah, monsieur. Vive la gloire. Vive Napoleon. You know, I admire your Napoleon very much.

KIRK: This is Mister DeSalle, our navigator. Doctor McCoy, our medical officer. Mister Sulu, our helmsman, and Carl Jaeger, meteorologist.

He states that he admires Napoleon (1769-1821).

TRELANE: Are you challenging me to a duel?

KIRK: If you have the courage.

TRELANE: Oh, this is better than I'd planned. I shall not shirk an affair of honour.

(He gets a box from the mantle-shelf. It contains a pair of duelling pistols)

TRELANE: A matched set. Just like the pair that slew your heroic Alexander Hamilton. And Captain, I never miss.

Dueling pistols were mainly from late 1700's or early-mid 1800's. Alexander Hamilton 1755-1804.

The events in this episode take place in 2267, so 900 years earlier would have been 1367.

At the beginning of the episode it was clear, at least to me, that Trelane was observing earth 900 years in the past. This is evidenced by Jaeger and Kirk's statements in the first quote.

Trelane makes reference to Napoleon who at most is only 600 years earlier. Dueling pistols are from the same time period. Alexander Hamilton again is from the same time period.

From the garb, decorations, dance, and music in Trelane's room it represented more of an 18th century decora then a 14th century.

I was confused by this. Is Trelane able to see any time period and only chooses this one? Is Trelane able to see any time period and likes this one (which would contradict what Kirk said in the first quote about 900 years), is it a writer's error/plot hole? Is there some other explanation?