Important Timelines in History and What that it means for the events in the drama
A number of you have asked, how long was the duration from E1 to E49?
I did some research linking history with the drama for a more precise answer. All this is based on Wikipedia and whatever I can find online:
1. Xuanwu gate incident: 2 July 626 AD
In the drama, Li Si Min killed Li Jiancheng in E2. So, E2 took place on 2 July 626
2. Nineth of September 626, Li Si Min became the new emperor of Tang Dynasty, when his father abdicated. The abdication was not shown in the drama. But, from the drama, we do know that by E20, he was already the emperor. Changge addressed him as such.
3. That scene at the river, where Li Si Min met the Khan and the Ashile troops, E20, that took place about 19 days after Li Si Min became emperor. So, the dramatic arrow shooting scene where Changge shot the arrow at the cups to save Li Si Min took place around 25-28 September 626.
So, E2 to E21 all happened rather quickly. From around July to September 626, all within the space of just three months. So, the grassland scene when she had her 1st period, she was about 14 plus.
But after this, it became rather difficult to tie events in the drama to history. Many of the stuff in the drama and manhua must have been fictional, since Changge and AS were fictional characters.
To place the next series of event in the drama to history, we will need to fast forward quite a bit.
Point 4: New Year 630, which would be around Jan-Feb 630, after the Tang Dynasty had grown strong enough militarily to confront the Eastern Turkic Khaganate, General Li Jing was tasked by Li Si Min to attack them. He and his fellow generals and the Tang troops took the city of Ding Xiang. Empress Xiao and her grandson were returned to the Tang Dynasty. They had been held by the Khaganate.
This would mean the AS rescue scene in E48 took place just slightly after Jan-Feb 630. Our drama therefore ended around maybe March 630. Li Jing's attack was rather swift and took the Eastern Turks completely by surprise. This would be quite in line with the drama, which showed him to be a very good strategist.
This time frame would also be fairly in line with history as Princess Yi Cheng was killed around late March 630, Du Ru Hui died in Spring (April?) of 630. All this in E49.
So, Xuanwu gate 2 July 626, last episode April 630. Assuming there is not much time lapse between E1 and E2, the whole series too place over a time frame of 3 years 9 months.
If Li Changge was around 14 in episode 1, she was around 17 going on 18, when she and AS went to the grasslands. AS was 22 turning 23. Both of them were still very young.