Some old houses have ghosts, ours has a cat.

Last night around 7 o'clock i looked out the back kitchen window to see an orange cat standing politely by the door. He wasn't wearing a collar, he looked healthy, I had never seen him before, and I knew he didn't belong to any of my neighbours, but he seemed to want to be let in. I thought, Is he here to visit Sylvia? Has he run away from his new home to find his way back here? He seemed friendly so i gave him a treat, a move i would soon regret. Since he asked so politely, by a mew more like a high pitched screech, I gave him two more. Then he became persistant. He pushed the back door open and walked into the kitchen in the direction of Sylvia's food. I nudged him out the back door again and he immediately jumped up on the window ledge. Sylvia walked casually into the kitchen and stopped, wide eyed, when she saw our visitor. Every single bit of fur on her back stood on end until she realised she was protected by a pane of glass. She leapt up onto the window ledge, he jumped onto the steps, and she stared him down while he stared up at her. The two kitties stared for about half an hour. I finally opened her window and the hissing and growling began. She jumped outside and ran down the steps to look cute under the japanese maple while she waited for him to persue her. It became clear that he was not interested in Sylvia but determined only to get inside. He jumped in the window and barralled downstairs. I ran after him and got him outside though not without hissing and scratching. He repeated this, more blood and hissing, and finally settled at the top of the stairs to wait for his next opportunity. J warned me then that if Sylvia returned to find his smell everywhere she may not come home. I got J to chase orange cat off the property, which he had to do several more times. I had never seen such a persistent cat. Sylvia didn't come home so I left the window open for her and went to bed around 10:30, drunk from whisky and worry. At 3 I got up to see if Sylvia was home and found her sleeping on her chair. I noticed that her food bowl was empty so I filled it for her. I closed the window and went back to bed. Around 3.30 J and I both heard a sound in the dining room so we got up to check. Sylvia was crouched in the living room, hairs standing on end, growling, and the orange cat was sitting casually under the dining room table. Who knows how long he was in the house, how much food he ate (probably all of it), and what the hell he thought he was doing. I put him outside, petted Sylvia who was very, very upset, and went back to bed. We haven't seen him since. Is this a routine? Were we just a stop on his neighbourhood rounds or does he think this is his home? Is he a cat-food burgler? A cat rapist? Has anyone else ever seen a cat behave this way?