No. While 'Reign' is based on a true story, it takes many liberties for the sake of drama. It's a fictionalized account of Mary, Queen of Scots' reign, so not all events are portrayed exactly as they happened in history.
Northern Qi's past emperors reigned as follows:
Gao Yang: 550 - 557 AD, reigned for 7 years.
Gao Cheng: 557 - 560 AD, reigned for three years.
Gao Yin: 559 to 560 AD, reigned for one year.
Gao Yan: 560 - 561 AD, reigned for one year.
Gao Zhan: 561 - 565 AD, reigned for 4 years.
Gao Wei: 565 to 577 AD, 12 years in office.
Gao Heng, 577 AD, not long after his reign.
The reign of the king appeared in the first episode of the anime, Little Fox Demon Matchmaker.
While waiting for the TV series, you can also click on the link below to read the original work of " Little Fox Demon Matchmaker " to understand the plot in advance!
In my opinion, 'Reign on Me' isn't a true story. It likely combines imaginative elements to craft an engaging narrative rather than being a direct account of real-life events. Maybe there are some common themes or emotions that can be related to real life, but not the entire story.