The Ptolemaic military went in to decline before the Seleukid one and when the Seleukid empire did begin to collapse, the Ptolemies had enough internal troubles to keep them occupied from invading the Seleukids.Originally Posted by Danest
As for Carthage, as Watchman says the terrain between the lands was not so favourable, however there also seems to have been a friendly relationship between the two empires.
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