On 29 December 1691 Johann Reinhold Patkul returned to Riga from his mission to Sweden. Shortly after that the Livonian nobility asked Governor Soop for permission to meet on 28 February 1692. When Alvin Isberg in 1953 published his study Karl XI och den livländska adeln 1684-1695 he did not have access to the archive of the Livonian Governor General, so he could not fully examine how Governor Soop handled this issue and what sort of instructions he received from Governor General Hastfer, who for health reasons was in Germany. Anton Buchholtz, who in 1893 published a biography of Patkul, had access but choose to focus on the aftermath rather than on the prelude.
As far as I can tell from primarily the letterbooks (outgoing correspondence of Governor Soop) the request by the nobility was not made until mid-January 1692. The first mention of it is in a letter from Soop to Hastfer, dated 21 January. In this Soop states that the nobility has sent a letter to him asking for permission to meet at Dorpat. Soop had replied that it was most unusual to hold a Landtag at Dorpat and that the regulations clearly stated that it should be held at Riga or Wenden. There was, Soop had stated, no need to hurry. If many of the leading nobles found it difficult to meet outside Dorpat as they were members of the Court of Appeals, it was entirely possible to wait until the court's sessions had ended. Soop had also pointed out that he would find it difficult to come to Dorpat, so if the issues really were pressing the meeting should at least be held in Wenden.
The nobility had however been unwilling to accept Soop's decision, so he had eventually accepted their choice of Dorpat. In his letter he reminded Hastfer that the Governor General had earlier indicated that it would for certain reasons be better to keep such meetings away from Riga, so Soop hoped that Dorpat would be acceptable.
I have not found Hastfer's reply, but the content of it can be deduced from a subsequent letter from Soop, dated 18 February. Apparently the Governor General had refused to accept the reasons given by the nobility and on 3 February written to Soop explicitly forbidding them to meet at Dorpat. In the letter Soop states that the nobility had received the news with astonishment and suggested that it meant a complete ban. Soop had however replied that it did not: both Hastfer and Charles XI had approved their request, so they only needed to find a more acceptable place. The Governor had indicated that they should perhaps delay the matter somewhat and then meet at Riga, but after some deliberations the representatives of the nobility had asked permission to hold the meeting as soon as possible and at Wenden. Soop had after careful consideration of the instructions given to him by the King and by Hastfer decided to grant their wish. The meeting would begin in Wenden on 11 March with Soop present to keep an eye on things.
On 11 March Soop his first report from Wenden. He had arrived the previous day. His intention had been to present the nobility with proposals more or less immediately, but as very few of the nobles had arrived he was forced to wait. On 23 March Soop sent a more extensive report to Hastfer. It deals however almost exclusively with the resignation of Landrat Vietinghoff and does not all mention any remarkable developments. As Isberg noted in his dissertation - the key discussions at Wenden seems to have gone unnoticed by Soop despite the fact that he was present from 10 March to 17 March.
Some time later Hastfer independently found out what had really taken place at Wenden and immediately informed Charles XI. The King was not pleased - as Soop soon found out.
An odd detail is that according to Isberg the first report from Hastfer dated 19 May 1692 reached the King at the beginning of June. The King then replied on 14 June. However, in LVVA there is preserved a letter from Charles XI to Hastfer dated as early as 14 May, which refers to a letter by the Governor General from the 19th preceding (!).
Isberg built his version on Hastfer's letter to the King and a copy of the King's reply (in Riksregistraturet). The letter in LVVA is however an original, signed by Charles and countersigned by Carl Piper. According to a note it was received by Hastfer in The Hague on 12 July 1692. Could it really have been on the road for two months? It seems unlikely, but Hastfer apparently left Frankfurt am Main in April and continued to Ems and The Hague. Could this explain the delay or is the original incorrectly dated? A peculiar mistake to make as late as the 14th.
According to Isberg Hastfer had an informant in Wenden and this would seem to indicate that the King's original is in fact correctly dated: the informant writes to Hastfer already in mid-March, Hastfer gets this letter some weeks later in Frankfurt am Main (where he had stayed for several months) and then proceeds to inform the King on 19 April. Neither the informant nor Hastfer would likely have hesitated before acting on such a matter, so 19 May and 14 June would from that perspective seem unlikely. But it is perhaps best to leave the issue open for the time being.
LVVA, fond 7349, op. 1, vol. 44
LVVA, fond 7349, op. 1, vol. 46
LVVA, fond 7349, op. 1, vol. 142
Isberg, A., Karl XI och den livländska adeln 1684-1695. - Lund, 1953