The last will and testament of Doge Giustiniano Particiaco, ordering, among other things, the construction of a new church next to the ducal palace where the newly procured remains of St. Mark the Evangelist ought to be deposited.
Venice, represented by Doge Orso I Participazio, and the Patriarchate of Aquileia, represented by Patriarch Walpert, sign a treaty according to which the Venetian Doge agrees not to block the Aquileian port Pylum, but only under the condition that the patriarch stops with all the hostilities directed against the Church of Grado and exempts the Venetians from all the tolls on his territories, according to the old customs.
Doge Pietro IV Candiano reenacts a decree forbidding slave trading, originally promulgated by Doge Orso I Participazio, imposing further restrictions on dealings with slavers and regulating postal communication with the Byzantine imperial court.
Venetian Doge Pietro II Orseolo departs with his navy on a military expedition against Croats and Narantines in Dalmatia; on his journey, the doge stops at Poreč and Pula where he is cordially greeted by the bishops, clergy, and citizens of these Istrian cities (narrative account from John the Deacon’s Istoria Veneticorum).
Doge Domenico Selvo confirms the donation of various tributes and incomes to the Patriarchate of Grado, originally donated by his predecessor Doge Domenico I Contarini.
Aquileian Patriarch Ulrich II of Treffen launches an attack on Venetian Grado as he tries to subjugate the competing patriarchal see; he fails miserably and ends up locked in a Venetian prison where he “buys” his freedom by signing a new treaty with Venice and agreeing to a yearly tribute of twelve loaves of bread and twelve pigs that his Church would perpetually bring to the ducal palace of Venice before the Fat Thursday festivities (narrative accounts from later Venetian chronicles).
Pope Alexander III confirms the spiritual and secular jurisdictions of the bishops of Poreč.
Pope Alexander III confirms the metropolitan jurisdictions of the incumbent Aquileian patriarch, institutes a new suffragan bishopric in Koper, grants him the pallium, and corroborates all the possessions and titles of the Aquileian Church, including the "County, the March, the Duchy," the regalian rights and imperial privileges.
Emperor Frederick I confirms the rights and possessions of the Bishopric of Torcello.
In response to the plea of the citizens of Koper, Doge Orio Mastropiero and the Commune of Venice issue a privilege to Koper, constituting it the only licensed port for salt trade in entire Istria, from Pula to Grado, and granting it a galley by which the citizens of Koper are to oversee the salt trade along the western coast of Istria; the privilege is accorded for twenty-nine years.
Patriarch Wolfger confirms to the monastery of Saint Nicholas of Lido in Venice the privileges and donations issued by his predecessors, patriarchs Pelegrin I, Ulrich II, Gottfried and Pelegrin II, including the right to freely travel across the Patriarchate and own property therein, three trading outposts in Aquileia, the monastery of St. Peter in Karst by Buje together with all of its properties, including the mill in Buzet and the right of advocacy relinquished by Advocate Maynard I of Gorizia.
Berthold V of Andechs, patriarch of Aquileia, and Count Maynard II of Gorizia, his advocate, promise to Doge Pietro Ziani and to the Commune of Venice the safety of Venetians living and operating within the confines of the temporal dominion of the Aquileian Church; promise to reimburse any Venetian if they end up robbed in the Patriarchate; to inform the Venetians if they find out that the Empire is planning any hostilities against them; and define the competences of the vicedominus of Aquileia; Venetians are promised exemptions from customs duties throughout the secular dominion of the Aquileian patriarchs and privileged judicial status.
Master Vivian, chaplain of the Patriarch of Aquileia and procurator of Count Meinhard III of Gorizia, presents letters to Doge Jacopo Tiepolo demanding observance of their agreement prohibiting any reprisals against the count (under penalty of 10,000 marks), prompted by a case involving robberies of Venetian citizens in the count’s jurisdictions, to which the doge affirms his compliance.
The communes of Venice and Pula sign a new peace treaty and agree on ten articles regulating their future relations.
The envoys of the Aquileian Patriarch Berthold negotiate a new peace treaty with Venice, ending all the conflicts regarding trade, traffic, salt production, dues and the restitution of movable and immovable properties, confirming and reinstating the old pacts signed between the two dominions.
Count Maynard III of Gorizia, the advocate of the Church of Aquileia, designates Ranieri Geno, the doge of Venice, as his official arbitrator in all the disputes he and his subjects have had with the Commune of Venice and the Venetian subjects.
Gregory of Montelongo, patriarch-elect of Aquileia, signs a treaty with Doge Ranieri Zeno and the Commune of Venice, renewing the old pacts signed between his predecessors and the Venetians, guaranteeing the safety of Venetian merchants throughout the Patriarchate, their privileged judicial status, abolishing all the newly instituted fees, and terminating the disputes between the two dominions.
Gregory of Montelongo, patriarch of Aquileia, voices his objections and presents his interpretation of certain articles of the pact signed with the doge and the Commune of Venice in front of the Venetian Great Council.
Manfred Cagapisto and Jacob Porrezionis, the official representatives of Aquileian Patriarch Raymond della Torre, conclude a new treaty with Doge Lorenzo Tiepolo and the Commune of Venice, reestablishing the relations as defined in a previous treaty from 1254 signed between Patriarch Gregory of Montelongo and Doge Ranieri Zeno; the representatives of the patriarch also promise to have the count of Gorizia sign the treaty once he settles his differences with the incumbent patriarch, to reimburse to the Venetians all the damages that they had suffered during the period in which the 1254 treaty had not been respected by the patriarchs, and to make sure that all the roads remain free and open to Venetian merchants.
Giovanni Dandolo, the doge of Venice, gives instructions to his ambassadors at the court of the Aquileian patriarch [Raymond della Torre], advising them on how to proceed on a number of issues, including the problems surrounding the Venetian jurisdictions in Istria, for which he recommends procuring a lease of the patriarch’s rights in the region.
The Great Council of Venice deliberates on the offered subjection of the Commune of Piran and decides to accept it.
Venetian Doge Giovanni Dandolo officially accepts and ratifies the subjection of the Commune of Piran.
With the help of Fulcher, the bishop of Concordia, a peace treaty is reached, signed between Venice on the one side and the Patriarchate of Aquileia, the count of Gorizia, and the Commune of Trieste on the other, ending the war that had begun in 1283.
Records of negotiations between Venice and Patriarch Raymond della Torre regarding jurisdictions in Istria, mediated by Bishop Bernard of Tripoli: first, Venice elects its negotiators; second, Patriarch Raymond issues his statement; third, the Venetian envoys present their terms in two separate statements; finally, Patriarch Raymond responds to Venetian terms and a semblance of a peace treaty begins to take shape.
The Commune of Venice – represented by the deputies of the doge, who was too ill to attend personally, and the Great Council – constitute five procurators to enter into arbitration with Pope Nicholas IV and Bishop Bernard of Tripoli regarding the dispute with Aquileian Patriarch Raymond della Torre over Istrian jurisdictions and to sign a truce or a peace treaty with the same prelate.