The Lutheran Reformation webpage, "What is a Lutheran?," states:

What are the Smalcald Articles and the Treatise on the Power and Primacy of the Pope?

"In 1537, Martin Luther was asked to prepare a statement of Lutheran belief for use at a church council, if it was called. Luther’s bold and vigorous confession of faith was later incorporated into the Book of Concord. It was presented to a group of Lutheran rulers meeting in the town of Smalcald."

Huh? "In 1537..."?!?

How about August 20, 1536? According to Friedrich Bente's Historical Introduction to the Lutheran Confessions:

"Luther had received the order to draw up these articles as early as August 20, 1536. September 3 [Chancellor to the Elector of Saxony, Dr. Gregory] Brueck wrote to the Elector on this matter: “I also delivered to Doctor Martin the credentials which Your Electoral Grace gave to me, and thereupon also spoke with him in accordance with the command of Your Electoral Grace.He promised to be obedient in every way. It also appears to me that he already has the work well in hand, to open his heart to Your Electoral Grace on religion, which is to be, as it were, his testament.” (p. 242)

"It was presented to a group of Lutheran rulers meeting in the town of Smalcald.

What?!? Not according to Bente:

"[I]t cannot be proved that he [Chancellor Brueck] directly and expressly mentioned them or submitted them for discussion and adoption." (p. 244)

"According to this report [of the Strassburgers], then, Luther’s articles were neither discussed nor adopted at the official meeting of the princes and estates belonging to the Smalcald League." (p. 246)

"As to the articles of Luther, Veit Dietrich reports that they were privately circulated at Smalcald and read by all. They were also to be read at the meeting of the theologians on February 18. (C. R. 3, 371.) As a matter of fact, however, neither a public reading nor a real discussion, nor an official adoption resulted." (p. 247)

"Luther’s articles, however,were nevertheless adopted at Smalcald, though not by the South Germans. When all other business had been transacted, they were presented for voluntary subscription. Bugenhagen had called the theologians together for this purpose. He proposed that now all those who wished (qui velint) should sign the articles Luther had brought with him. Hereupon Bucer declared that he had no commission to do this." (p. 247)

"Although, therefore, the subscription of the Smalcald Articles lacked the official character and was not by order of the Smalcald League as such, it nevertheless is in keeping with the actual facts when the Formula of Concord refers to Luther’s Articles as 'subscribed at that time [1537] by the chief theologians'.” (p. 248)