From a specified time in the past.
“I met him last year, but haven’t seen him since.”
From: referring to a period of time ending in the present and defining it by the point in time at which it started, or the period in which its starting point occurred.
Continuously during that period of time.
“I have known her since last year.”
Gone; gone by; gone away; passed; passed away.
“in days ago/in days agone”
Nearly gone; dead 19th century]]
“Woe the day- she is agone!”