Produced from 1950 until 1985, Ref. 2499 is recognized as one of the most important wristwatches made by Patek Philippe. The successor to Ref. 1518 and the predecessor to Ref. 3970, Ref. 2499 holds a distinguished place among the firm's exceptional perpetual calendar chronograph wristwatches. With only 349 pieces made in total, or an average of only nine pieces per year, it is an extremely rare piece and one that was made with the outmost attention paid to each detail. This model underwent four major evolutions over its 35-year production run. The first was distinguished by its square chronograph pushers and, in most examples, a tachometer scale. The second series introduced round chronograph pushers. The third series, to which the present example belongs, was produced from 1960 until 1978. It is distinguished by its simple dial design, having dropped the tachometer scale. Examples made after 1978 belong to the fourth series of the reference, and are referred to as Ref. 2499/100. These pieces have raised sapphire crystals and modified bezels to accomodate them.
Reference 2499 is illustrated in Huber, M., Banbery, A., Patek Philippe Wristwatches, Vol.2, p.302.