Translation:They bought one thousand seven hundred animals then.
In English there is a difference in meaning to the alternative translations suggested above. The official version suggests that at some time in the past, which is under discussion, they bought the animals, the alternatives indicate that having already done something else "they then bought..." 1. Long ago we lived in Brno and we bought the animals then. 2. We bought food and then we bought the animals. Can Czech distinguish between these.