Queen Seondeok: Silla's First Queen and the Cheomseongdae Observatory

If you go to see Cheomseongdae, the stone observatory near Gyeongju's royal tombs, the natural question is whose reign it belongs to — and the honest answer is that the heritage authority does not quite say.

The Korea Heritage Service writes that Cheomseongdae is presumed to have been built in the reign of Queen Seondeok (632–647). Not "was built". Presumed.

And her own biography returns the compliment: the Encyclopedia of Korean Culture's entry on Seondeok lists Bunhwangsa in 634, Yeongmyosa in 635 and the nine-storey pagoda at Hwangnyongsa in 645 — and never mentions Cheomseongdae at all.

This article follows what the Encyclopedia of Korean Culture does record about her reign, and then what you can actually read in the stones of Cheomseongdae.

At a glance

Reigned 632–647
The twenty-seventh ruler of Silla. Surname Kim, given name Deokman, eldest daughter of King Jinpyeong.
Raised by a council
Jinpyeong died without a son, and the Hwabaek Council raised her to the throne and gave her the title Seongjo Hwanggo.
About 9 m, 27 courses
Cheomseongdae is about 9 m high, a bottle-shaped cylinder of 27 courses of fan-shaped stone on a base, with a well-shaped top.
Presumed, not recorded
The Korea Heritage Service dates the observatory to her reign as a presumption, and her own biography does not mention it.

How a woman came to the throne of Silla

The mechanism is specific, and it is not "she inherited it".

King Jinpyeong died without a son. The Hwabaek Council raised her to the throne and offered her the title Seongjo Hwanggo. What made that possible was the special royal-lineage consciousness called seonggol — hallowed bone.

Two things are worth separating there. The Hwabaek was an aristocratic council, so the accession was decided by an assembly rather than simply passing down. And seonggol was a rank of birth so narrow that when it ran out of men it did not run out of members — which is why a daughter could hold it and a male cousin could not.

Her first acts read as a new ruler buying consent. In 632, her first year, she put the minister Eulje in charge of state affairs and sent officials throughout the country to relieve the people; in 633 she remitted the taxes of the provinces and counties for a year.

In 634 she founded Bunhwangsa, in 635 Yeongmyosa, and in 634 she adopted her own era name, Inpyeong. An era name is not decoration: declaring one is a claim to count time from your own throne rather than someone else's.

642 — the year the walls fell in

Then the reign turns.

From 642 Silla came under attack in earnest. Baekje's King Uija took more than forty fortresses on the western border. Danghangseong, Silla's foothold toward the Han River, was attacked by Goguryeo and Baekje together. And the Baekje general Yunchung took Daeyaseong, the foothold on the Nakdong.

Two strategic corners in one year. She appointed Kim Yushin military governor of Apryangju to hold off the Baekje attack, and in 643 sent an envoy to Tang to ask for rescue.

She also called Jajang home from his studies in Tang. With the queen's active backing he entered politics deeply, and used Buddhist thought as a means of strengthening royal authority — the symbol of which was the nine-storey wooden pagoda raised at Hwangnyongsa in 645, some 80 metres tall.

Eighty metres of timber is a defence budget as much as a devotion. Hwangnyongsa is a foundation platform in a field today; standing on it, the number is the only way to feel the building.

A sentence from Tang, and a revolt

A remark about Seondeok with serious consequences was made by someone else.

When Silla's request for rescue reached him, Emperor Taizong of Tang told the envoy that the problem was this: "because a woman rules, there is no authority, and so you are invaded by both Goguryeo and Baekje."

That remark made waves in Silla's own politics. In the first month of 647 the senior councillor Bidam and Yeomjong, with other jingol aristocrats, revolted on the pretext that the queen governed badly. Kim Chunchu and Kim Yushin put it down — and in the turmoil of that civil war the queen died, in the sixteenth year of her reign. Her posthumous name was Seondeok and she was buried at Nangsan.

The two men who suppressed the revolt are the two who go on to unify the peninsula, which is the end of the Three Kingdoms in one sentence. Her reign is where that partnership was made.

What you are actually looking at in Gyeongju

Cheomseongdae rewards being read closely, and the Korea Heritage Service's description tells you what to look for. It stands in Inwang-dong, Gyeongju, near the Daereungwon royal tombs; check its opening hours on the place card at the end of this article before you go.

The base carries a bottle-shaped cylindrical body, and the whole is about 9 m high. The cylinder is 27 courses of fan-shaped stone. The outside is smoothly dressed; inside, the tails of the stones stick out and the wall is uneven.

That asymmetry is the useful detail. It was finished where people would see it and left rough where they would climb.

There is a window on the south-east side. Below it the shaft is packed with rubble; above it the shaft is hollow all the way to the top. At the top, long stones interlock in a well shape and their ends pierce out through the wall — and the same appears at courses 19–20 and 25–26, which looks suited to bracing a ladder inside. An old record says that "a person goes up through the middle."

So the route was: a ladder outside up to the window, in through the window, then a ladder inside to the top. Count the protruding stone ends from the ground and you can see where the second ladder rested.

The Korea Heritage Service calls it the oldest astronomical observatory in the East — and it explains why a state would build one at all: astronomy set the timing of agriculture, and in an ancient state the reading of the sky was used to divine the fortunes of the country, so it was political as much as scientific.

Read that beside 642 and the building stops being a curiosity.

Do not take a photograph from one side only. The smooth outside is the easy picture; the thing that tells you how it was used is the row of stone ends poking through the wall about two-thirds of the way up. Walk around until you find them.

Places connected to Seondeok

Frequently asked questions

Did Queen Seondeok build Cheomseongdae?

The Korea Heritage Service says only that it is presumed to have been built in her reign, 632–647. Her own entry in the Encyclopedia of Korean Culture lists Bunhwangsa (634), Yeongmyosa (635) and the Hwangnyongsa pagoda (645) but does not mention Cheomseongdae. The honest answer is that the attribution is a presumption, not a documented fact.

How did a woman come to rule Silla?

King Jinpyeong died without a son, and the Hwabaek Council raised her to the throne with the title Seongjo Hwanggo. The background was seonggol — a hallowed-bone royal rank narrow enough that a daughter within it outranked men outside it.

What did she actually do?

Relief and tax remission in 632–633, the founding of Bunhwangsa and Yeongmyosa, her own era name Inpyeong, the appointment of Kim Yushin against Baekje, an appeal to Tang for aid in 643, and the recall of the monk Jajang, under whom the nine-storey pagoda at Hwangnyongsa was raised in 645.

How did her reign end?

In the first month of 647 the senior councillor Bidam and Yeomjong revolted on the pretext that a queen governed badly — a pretext that echoed Tang Taizong's remark to a Silla envoy. Kim Chunchu and Kim Yushin suppressed it, and the queen died during the turmoil, in the sixteenth year of her reign.

How tall is Cheomseongdae and how was it climbed?

About 9 m, built as 27 courses of fan-shaped stone. There is a window on the south-east side; the shaft is packed with rubble below it and hollow above. Stone ends protrude at the top and at courses 19–20 and 25–26, which appears suited to bracing a ladder inside, and an old record says a person went up through the middle.