The now-confirmed transfer of Petr Cech to Arsenal makes perfect sense. The Gunners have long looked in need of a consistent, confident goalkeeper, Cech is one of the Premier League's greatest and available for purchase.

But then, when you consider Arsene Wenger's history in the transfer market, the deal begins to look something of an anomaly.

According to reports, Cech has cost Arsenal about £11.5m. For a 33-year-old goalkeeper, such a deal marks a drastic change from Wenger's previous policy in the transfer market, as demonstrated in the below graph of every Wenger signing at Arsenal (excluding loans).

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Since instigating a mini footballing revolution at Arsenal in 1996, Wenger has spent just over £25m on 12 goalkeepers – 4.39 per cent of his £526.2m total. Richard Wright, signed for £7.9m from Ipswich Town in the summer of 2001, remains the costliest man between the sticks in the Wenger era.

Yet if Cech's position is one Wenger has traditionally avoided splashing out on in recent years, his age is even more of an exceptional attribute.

In 18 seasons, the Frenchman has signed just eight players aged 30 or older, three of whom were keepers and just three aged older than Cech is now – Jens Lehmann, Sol Campbell and Mart Poom.

In fact, at 33 Cech is over 10 years older than the average age of a Wenger signing, which stood at 22.7 before his arrival.

After signing 30-year-old Sebastien Squillaci in 2010, the Arsenal boss explained his view on signing veteran players depended on their position: "It's not over 30, it's over 32. So when you have a player [who is] 32 he will just get a one-year contract. It depends on the positions as well. If a central defender, then no problem to sign them until 34. But a striker is different. After 32 you go from year to year. A midfielder as well, after 32 you go from year to year."

So perhaps Wenger has always been open to signing a getting-on goalie after all. Jens Lehmann, Wenger's most commonly used keeper after David Seaman was aged 33 when he joined Arsenal and proved to be far more successful than any of those who came after him (Champions League final red card aside).

There is one element of the transfer that is not as uncommon, however; the fact the seller is Jose Mourinho at Chelsea – no Premier League manager has sold more players to Wenger at Arsenal.

Admittedly, that's just two in the form of William Gallas and Lassana Diarra – as Wenger has cast his net wide, signing 108 players from 82 different clubs. Former club Monaco have provided the most players (4).

*All data from Transfermarkt.co.uk, Cech fee based on reported figures.