He was named for William the Conqueror. He came into a home with five dogs and six cats and let everybody know that he was now in charge. He was supremely confident as a kitten — you might say arrogant — and he conquered every room he entered.

Mostly, though, he conquered my heart.

It was my ex-wife who found him and brought him home in 1999. I can’t say that I was thrilled to add another animal to the menagerie, but there was something about him that was impossible to say no to.

So he became the seventh and youngest cat in the household, but there never seemed to be a moment when he wasn’t in charge.

Eventually, all the others died of old age or disease. At 16 years old, William was the oldest — the unquestioned king of his domain.

Just about 10 days ago, he started acting lethargic. After a few more days, he had little interest in food. Early last week, a trip to the vet confirmed my worst fear. My little friend was very sick.

William had a tumor the size of a lemon in his abdomen. There were signs that it was attached to something related to his gastrointestinal system. His age and his condition meant that surgery wasn’t an option. All we could do is put him on steroids and try to “jump start” his appetite. If he would start eating again, he might have many months of quality of life left. But if he wouldn’t start eating, he had no chance.

Just five days after that diagnosis, William died Sunday morning about 9 a.m. He never seemed to be in pain. His cancer-ravaged body simply shut down as I held him. All of a sudden, he was gone — and his battle with the cancer was over.

For me, my cats and dogs have been my family over the years. I’ve never cried over the death of a person I’ve known, but I’ve felt serious despair and loss about the deaths of these small creatures. Especially over the last 15 years since I divorced, my cats and dogs have been very important. At times, they’ve seemed to be my only real purpose — the only creatures who really needed me.

Animals are better than humans in one key way. There’s no pretense to them. You don’t have to wonder if they mean what they “say.” Cats are great examples to everyone who wants something. They never shut up until they get what they want. I’m prone to quit asking for what I need after the first “No,” but a cat never feels guilty about demanding what it needs.

In the best of cases, the relationship between a person and an animal is symbiotic. Each needs the other for something and also supplies something that matters to the other. For 16 years, William has been there for me and supplied love and companionship. I’ve given him food, shelter and love in return.

William was the last of the animals that my ex-wife and I had when we divorced 15 years ago. Over the years, we’ve lost Oscar, Henry, Thomas, Dusty, Elizabeth, Maggie, Olivia, Lucy, Munchkin and Alex. Losing each one hurt in his or her own way, and watching them go through this final stage of life never gets any easier.

In the emails with my ex to keep her informed about what was going on with William, she pointed out something very important about this difficult process of being with them while they die.

“…I think [taking care of our animals as they die] is one of the most important things we can do for the animals we love,” she wrote. “They have spent their lives sitting beside us during good and bad times, and they poured so much life into our everyday experiences. Being with them as they die is the last thing we get to do for them, and it is one of the most important. How much more comforting it must be to them to have the people they love and know beside them as their bodies slowly shut down.”

William was a very important part of my life. Others have come before him and others will come after him. But he will always occupy a unique place. He will always be special.

He will always be the unwanted homeless kitten who boldly walked into my home and heart — and took over.