Sussex skipper Chris Adams has joined Mark Ramprakash and Carl Hooper by completing a full set of hundreds against all 18 counties.
Adams went on to make the fourth double hundred of his career, but he admitted some of the gloss was taken off his achievement by what followed after he was out for exactly 200.
Sussex lost their last six wickets for 24 runs and had to follow on against Northamptonshire at Hove.
Adams said: "I didn't expect that collapse, but it indicates that we're not 100 per cent at the moment.
"I badly wanted another double hundred and I've been aware that I needed Northants for a full set for a while so it's nice to finally get there."
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