Frank is a 90 pound lap dog that we rescued from Boston Animal league when he was 5.  We have had him for about 4 years now.  He was turned into the shelter by a family who had only had him for a few weeks because he was showing aggressive behavior towards the husband of the family.  He had become very protective of the wife in the short period of time they had him and would bark/growl/and charge the man if he came near her.  Before that, he was turned in for allergies, which we have since gotten under control and he is doing much better.  

He is a happy dog who loves to play and mostly sleep/snuggle.  Frank is a bit of a mixed bag. On one hand, he is the friendliest, happiest dog you will ever meet, but in certain circumstances he becomes very protective and can become aggressive.  He has a very loud mastiff bark and is not afraid to use it when trying to protect his humans.  He gets along great with his dog brother and sister and loves all big dogs.  Frank has displayed aggressive behaviors ever since we have had him, but they seem to have gotten worse over the years.  Frank will charge at the door if there is a knock.  He also charges at people when they enter the house/come onto our property.  He can be easily called back most of the time, but not 100%.  Lately Frank's aggression towards small dogs has become incredibly concerning.  Frank is the type of dog that LOVES to play, chase, and wrestle other dogs, but when a small dog is around it is like he sees it as something to kill.  He has started fights with a few small dogs that thankfully ended ok, but could have been much worse.  He is incredibly powerful and when in a "crazed" mindset becomes very hard to control.  When we first rescued Frank, he had to be trained a lot in order to be submissive to us, but once he realized that we were in control, he has been great.  If you are in his circle, he will have your back no matter what, even when it is not necessary - i.e. someone knocking on the door.  There is never a thought in our mind that he would harm us, but he would absolutely harm someone that isn't in our circle if he felt threatened or that he had to protect us.