One of the star attractions at Yorkshire Wildlife Park as died.
News of Simba the lion's death, from "ongoing age-related health issues" prompted an outpouring of emotion by visitors who had seen or spent time with the animal over the years.
More than 500 people posted messages on the Doncaster park's social media channels.
One wrote: "Beautiful Simba, big hugs to all the staff, he will be missed by you and the visitors to the park."
Another commented: "He had a wonderful life at YWP. Thank you for rescuing him and all the care the team gave him. Xx"
The news was released on World Animal Day with the park saying: "Simba was just one of 13 amazing Lions YWP rescued and whose legacy will continue for years to come."
Simba was one of 13 malnourished lions rescued in 2009 from a dilapidated zoo in Romania as part of the YWP's landmark Lion Rescue campaign.
The pride was being kept in concrete pens. Staff at Oradea Zoo wanted to save them, but were struggling with facilities and funds.
They were rehoused in the seven-acre Lion Country at the South Yorkshire park following a public appeal that raised £150,000.
Simba was approximately 15 years old. His age and those of the other lions had to be estimated as no paperwork was available when they were rescued.
He was the last male lion at the park following the death of Ares, who was put down earlier this year due to his "declining health".
Simba's father, Johnny Senior, died in 2012 at the age of 30.