A kingdom they portend thee, but what kingdom, / Real or allegoric, I discern not; Nor when: eternal sure--as without end, - John Milton, Paradise Lost.
If something portends an event or occurrence, it indicates that it is likely to happen in the future. The change did not portend a basic improvement in social conditions. to be a sign that something is going to happen, especially something bad (portendere , from tendere )
[ por-'tend, pOr- ] (transitive verb.) 15th century. From the Latin portendere (“to foretell”), from por- (“forward”) + tendere (“to stretch”), present active infinitive of tendo.