Marty Schottenheimer -- one of the NFL's all-time greatest head coaches -- died on Monday after a lengthy battle with Alzheimer's ... his family announced Tuesday.
He was 77 years old.
The coach had fought Alzheimer's since 2014 ... but was moved to a North Carolina hospice facility last month after his family said he was suffering from "complications from his disease."
Schottenheimer's wife, Pat, said at the time, "As a family we are surrounding him with love and are soaking up the prayers and support from all those he impacted through his incredible life."
"In the way he taught us all, we are putting one foot in front of the other ... one play at a time."
Pat and the rest of the Schottenheimer family told ESPN's Chris Mortensen Marty passed on Monday ... adding the former coach will have a private family service soon with a public memorial service at a later date.
A private service will be held by his family, and a memorial service to celebrate his life will be conducted at a later date, according to the Schottenheimer family.
Schottenheimer was a head man in the NFL for 21 years ... and is 1 of just 8 men to win at least 200 games in the league as a head coach.
He began his head coaching career with the Cleveland Browns in 1984 -- and later went on to coach Joe Montana and Marcus Allen in Kansas City starting in 1989.
Schottenheimer went on to spend 10 total years with the Chiefs -- piling up a 101-58-1 regular-season record. He took the team to 7 playoff appearances -- and even brought them to the AFC Championship game in 1993, where they lost to the Buffalo Bills.
Marty continued his coaching career with Washington before moving to the San Diego Chargers. He was named Coach of the Year there in 2004, when the team went 12-4 and won the AFC West.