Editing 1638 (section)

=== July–September ===
* [[July 16]] &ndash; [[Thirty Years' War]]: The [[siege of Saint-Omer]] ends after almost two months as the French-held Flemish city falls after being besieged by Spanish and German troops.
* [[July 20]] &ndash; Scottish [[Covenanter]]s meet at [[Muchalls Castle]] to compose a response to the 14 demands of the [[Bishops of Aberdeen]].<ref>J. P. Edmond, ''The Aberdeen Printers: 1638-1682'' (J. & J. P. Edmond & Spark, 1884) p.65</ref>
* [[July 28]] &ndash; [[Thirty Years' War]]: Swedish Army Field Marshal [[Johan Banér]] begins a destructive campaign against the [[Duchy of Pomerania]], held by the Holy Roman Empire. 
* [[August 15]] &ndash; The Portuguese expedition led by [[Pedro Teixeira]] completes the first ascent of the [[Amazon River]], crossing the Quijos River and arriving at [[Quito]] in [[Ecuador]] soon after (the same trip had been made in the opposite direction, in [[1541]]).
* [[August 22]] &ndash; [[Franco-Spanish War (1635–59)]]: The [[Battle of Getaria]] is fought between the navies of France and Spain, with the French sinking all 17 Spanish Navy ships and killing 2,000 Spanish sailors and officers.<ref>Guy Le Moing, ''Les 600 plus grandes batailles navales de l'Histoire'' (in French)(Marines Editions, 2011) p.309</ref>
* [[August 27]] &ndash; [[Tayyar Mehmed Pasha]] becomes the new [[Grand Vizier of the Ottoman Empire]] after [[Bayram Pasha]] dies while fighting in [[Baghdad]].
* [[September 6]] &ndash; The Finnish [[mail]] service, predecessor of [[Posti Group]], is established.<ref>"Suomen julkinen postilaitos perustettin 6.9.1638, joloin hyvakayttiin Tukholman-Kakisalmen linjalle postitaksa". Aili Rytkonen Bell and Augustus A. Koski, ''Finnish Graded Reader'' (Foreign Service Institute, 1968) p. 268</ref>
* [[September 21]] &ndash; The [[Treaty of Hartford (1638)|Treaty of Hartford]] is signed, ending the [[Pequot War]] between British American colonists and the Pequot.
* [[September]] &ndash; John Spofford arrives in [[Boston Harbor]], on the ship ''John of London'', and is one of the first people to establish Rowely, [[Essex County, Massachusetts]].