“At almost any time, anywhere, we can look at the clock – street, wrist or on a mobile phone – and find out the exact time. Everywhere it is counted from midnight and noon. But earlier – even just a few centuries ago – it was not so: the answer to the question “what time is it?” Could be not only inaccurate due to the imperfection of the clock, but also ambiguous, and even incomprehensible. 
In order to prepare for understanding the information of old chronicles and documents about eclipses, we will discuss some details of the “time calculation” of the day. “

 

My thanks to Jordan Tabov for his wonderful help and guidance.

Here is an interesting article:

 

Twelve eclipses of the 
era of Constantine the Great

Yordan Tabov, Nikolai Tomov