2 Corinthians 1:1

And Timothy

(κα Τιμοθεος). Timothy is with Paul, having been sent on to Macedonia from Ephesus (Acts 19:22). He is in no sense co-author any more than Sosthenes was in 1 Corinthians 1:1.In all Achaia

(εν ολη τη Αχαια). The Romans divided Greece into two provinces (Achaia and Macedonia). Macedonia included also Illyricum, Epirus, and Thessaly. Achaia was all of Greece south of this (both Attica and the Peloponnesus). The restored Corinth was made the capital of Achaia where the pro-consul resided (Acts 18:12). He does not mention other churches in Achaia outside of the one in Corinth, but only "saints" (αγιοις). Athens was in Achaia, but it is not clear that there was as yet a church there, though some converts had been won (Acts 17:34), and there was a church in Cenchreae, the eastern port of Corinth (Romans 16:1). Paul in 2 Corinthians 9:2 speaks of Achaia and Macedonia together. His language here would seem to cover the whole (ολη, all) of Achaia in his scope and not merely the environment around Corinth.