Two broken bass strings in one tuning?????

[Samuel Choy]

What's up with this? I was tuning a Baldwin console tonight and two bass 
strings broke!!! F2 (one of the unisons) and G1. I can't figure out why they 
broke. There was no visible rust on the strings. I barely raised the pitch 
when they broke. When the second broke, I decided to stop tuning. I didn't 
have enough time to attempt a splice on the strings, so I'm going to go back 
tomorrow.

Any suggestions? Any ideas as to a cause? I was hoping to look up the SN in 
my Pierce Piano Atlas, didn't see it. It's 809893, but the atlas didn't list 
any SN close to that, so I wonder if I copied it wrong. I wish I had asked 
the owner how old the piano is.

Thanks. Sam.