Not just bull breeds were used in the square back then though, and still not. I think any dog, if deemed to be standing a chance, was used. If memory serves me correctly, then there's mention of a golden retriever who was used in the pit in Fitzbarnard's Fighting Sports book, and also in Lucas's Hunt and Working Terriers book, there's the Airedale dog, Thunder, that was used too....I think. My memory might be playing tricks on me. Certainly from my own experience, I had a little 20" lurcher once that adored a tear-up with my bull terriers