since the consequences of such a step could not be overlooked. After changes to the draft constitution by the provisional north German parliament, the plenipotentiaries approved the amended constitution on 16 April 16. The Senate's message to the Burgerschaft (drafted by Kirchenpauer) asked them to consent, even though it did not correspond to the wishes of all concerned. The Hamburg Senate, like others, had to give up essential parts of its state independence, but this was necessary to achieve an agreement. The Burgerschaft ratified the constitution on 15 May 15, 1867 and it came into force on 1 July 1, 1867, founding the North German Federation. Constitution of the North German Federation Although Hamburg joined the North German Federation, it remained outside the Customs Union. The federation's constitution included special arrangements for Hamburg and the other Hanseatic cities: Article 34: The Hanseatic cities of Lübeck, Bremen and Hamburg with appropriate districts for this purpose or their surrounding area, shall remain as free ports outside the Community customs border until they apply for their inclusion in the same. Article 38: The yield of the customs duties and the excise duties specified in Art. 35 flows into the Federal Treasury. Following clauses defining “yield”, it continued: The areas outside the Community customs border contribute to federal expenditure through the payment of an Aversum (a specific discretionary lump sum). Also Article 35 specified that the Federation had exclusive charge of measures required in areas outside the Customs Union to secure the common customs border. The Aversum After the founding of the North German Federation, Kirchenpauer and Versmann went to Berlin in the summer of 1867 to negotiate the Aversum. The North German Federation was funded by (a) customs duties forming the common external tariff and (b) consumption taxes (tax on spending on goods and services). Non-members of the Customs Union instead paid a compensatory lump sum into the Federal Treasury, which was legally regarded as a complete substitute for the indirect taxes which had not been paid. The Aversum consisted of two parts. Firstly, each year the total customs and consumption tax income was divided by the population of the Customs Union, then applied pro rata to the population of each Hanseatic city living outside the customs line. Secondly, a supplement was added, per head of the population of these free zones. The Aversum supplement was in 1867 set at 2.21 marks per