Lesson Plan: The Toll at the Narrow Place

A Time Rhymes lesson pairing Denmark's Sound Dues (1429–1857) with the US Naval Blockade of the Strait of Hormuz

---

Overview

• Grade Level: AP US History / AP World History / AP European History / Social Studies (grades 9–12)

• Time Required: Adaptable: bell-ringer (7 min), single class (45 min), or extended (2 classes)

• Historical Period: Late Medieval through Modern Europe (1429–1857), with extension into contemporary geopolitics (2026)

• Modern Connection: The Trump administration's announced naval blockade of the Strait of Hormuz, interdicting vessels that have paid tolls to Iran, framed explicitly in the language of chokepoint control and economic coercion

---

Learning Objectives

Students will be able to:

1. Identify and explain the geographic, economic, and political conditions that allowed Denmark to sustain the Sound Dues for 428 years, using specific evidence from the story and related sources.

1. Analyze how states have historically used geographic chokepoints as instruments of economic and military power, comparing the Øresund Strait to the Strait of Hormuz.

1. Evaluate the structural similarities and meaningful differences between Denmark's Sound Dues and the US naval blockade of the Strait of Hormuz, distinguishing between illuminating parallels and misleading ones.

1. Construct a written or oral argument about whether the current Hormuz crisis is more likely to resolve through military force or economic negotiation, using historical evidence to support their claim.

---

Before Reading

Anticipation Questions

Pose these questions before students read or listen. Do not provide answers yet. Ask students to write a two-sentence response to each, then share briefly with a partner.

1. Geography as power: Think of a narrow waterway, mountain pass, or land bridge anywhere in the world. Who controls it? What would happen if that controller demanded payment from everyone who passed through? Would the world accept that? Why or why not?

1. The cost of confrontation: If a country is doing something you find unjust but going to war to stop it would cost more than simply tolerating it, what should you do? Has the United States ever faced that calculation before?

1. Blockades and war: Under what circumstances, if any, do you think a naval blockade is justified? Is there a difference between closing a strait entirely and interdicting only the ships of one country?

---

Key Vocabulary

| Term | Definition | |---|---| | Sound Dues (Øresundstolden) | The toll levied by Denmark from 1429 to 1857 on all foreign ships passing through the Øresund Strait between the North Sea and the Baltic Sea | | Chokepoint | A narrow, strategically critical passage, whether a strait, canal, or mountain pass, whose control confers significant military or economic leverage | | Interdiction | The military act of stopping, seizing, or destroying enemy supplies, forces, or, in this context, commercial vessels | | Naval blockade | The use of naval forces to prevent ships from entering or leaving an enemy's ports or coastline; under international law, generally considered an act of war | | Free navigation (Freedom of the Seas) | The legal principle, codified in international law, that ships of all nations have the right to pass through international waters and straits without interference | | Rigsdalers | The Danish currency unit used in the 1857 Copenhagen Convention payment; the lump sum paid to Denmark to permanently abolish the Sound Dues | | Copenhagen Convention (1857) | The multilateral treaty signed by fourteen nations that abolished the Sound Dues and declared the Danish straits international waterways in exchange for a compensatory payment to Denmark | | CENTCOM | United States Central Command, the military command responsible for US operations across the Middle East and Central Asia |

---

During Reading

Guided Questions

Ask students to write brief answers to these questions as they read or listen. These are comprehension anchors, not discussion prompts.

1. The mechanism: How did Denmark's Sound Dues work? How did the toll evolve from a flat fee to a percentage of cargo value, and why did that change matter for Danish revenue?

1. The paradox of endurance: The story says the Sound Dues survived not because Denmark was the strongest power in Europe, but because the toll was "calibrated to extract the maximum revenue at the minimum provocation." What does that mean in practice? Can you find a specific example in the text?

1. The resolution: How did the Sound Dues actually end? Who paid, who benefited, and what legal principle was established by the 1857 Copenhagen Convention?

1. The framing: The story notes that Trump's announcement used the word "toll" to describe Iran's control of the Hormuz strait. Why might that word choice matter politically and legally?

---

After Reading

Discussion Questions

Progress through these in order. The first two are comprehension and analysis; the last is genuinely debatable.

1. Comprehension: The story argues that Denmark's toll survived for 428 years through "inertia, precedent, and the cold arithmetic of cost." Using specific evidence from the text, explain what each of those three factors means in the context of the Sound Dues.

1. Analysis: The story says the US blockade aims to open the Strait of Hormuz "on American terms." How is that goal structurally similar to what Denmark did at Helsingør? How is it different? Consider who is imposing the toll, who is paying it, and who benefits from the strait being open.

1. Causation: The Sound Dues ended not through military force but through a negotiated buyout. What conditions made that resolution possible in 1857 that might or might not exist in the current Hormuz crisis? Think about the number of nations involved, the availability of alternatives, and the legal frameworks in place.

1. Perspective-taking: The story presents both supporters and critics of the blockade. Identify the strongest argument on each side. Which do you find more persuasive, and why? What evidence would change your mind?

1. Debate question: The story ends with the claim that "the narrow place is always worth more open than closed." Is that true? Can you think of historical cases where a power benefited more from keeping a chokepoint closed than from opening it? Does that complicate the story's implied argument about how the Hormuz crisis should resolve?

---

The Parallel

These questions ask students to think critically about the historical analogy itself, not just the two events separately.

1. What the parallel illuminates: The Sound Dues story suggests that chokepoint disputes tend to resolve through economic calculation rather than military force, because the cost of war usually exceeds the cost of compliance or buyout. If that pattern holds, what does it predict about the Hormuz crisis? What specific conditions would need to be true for the prediction to work?

1. What the parallel obscures: Denmark in 1429 was a small kingdom extracting rent from European merchants. The United States in 2026 is a global superpower imposing a blockade on a regional power during an active conflict. What structural differences between these two situations might make the historical parallel misleading rather than illuminating? Consider the role of nuclear weapons, international law, and the involvement of major powers like China and India.

1. The limits of analogy: Historical parallels are tools for thinking, not predictions. What would a historian need to be careful about when using the Sound Dues as a framework for analyzing the Hormuz blockade? What questions does the parallel fail to answer?

---

Activities

Bell-Ringer (7 minutes)

"The Narrow Place" Map Exercise

Before playing the audio narration, display a split map: the Øresund Strait on the left (showing Helsingør, Helsingborg, and Kronborg Castle) and the Strait of Hormuz on the right (showing Iran, Oman, and the shipping lanes).

Ask students to spend 90 seconds writing answers to two questions on a notecard:

1. What do these two places have in common geographically?

1. Who benefits if each strait is open? Who benefits if it is closed?

Play the Time Rhymes audio narration (approximately 5 minutes). At the end, ask two or three students to share whether the story confirmed, complicated, or changed their notecard answers. Collect the notecards as an informal formative check.

---

Single Class (45 minutes)

Structured lesson with timing for each segment:

0:00 to 0:07: Bell-Ringer Map Exercise (as described above)

0:07 to 0:12: Vocabulary Preview Display the key vocabulary table. Ask students to identify which three terms they already know, which three are new, and which one they are most uncertain about. Quick show of hands for each. This takes two minutes and tells you where to focus.

0:12 to 0:17: Anticipation Questions Students write two-sentence responses to Anticipation Questions 1 and 2 (skip Question 3 for time). One-minute pair-share. Do not resolve the questions yet.

0:17 to 0:27: Reading or Listening Students read the full story independently, or listen to the audio narration while following along. Students annotate for the four Guided Questions, writing brief margin notes or responses on a provided graphic organizer.

0:27 to 0:37: Structured Discussion Use Discussion Questions 1 through 4 in sequence. Spend approximately two to three minutes per question. Use cold-calling or a visible random selector to ensure broad participation. Write key student claims on the board in two columns: "Sound Dues" and "Hormuz Blockade."

0:37 to 0:43: The Parallel Analysis Introduce Parallel Questions 1 and 2 as a think-pair-share. Students have 90 seconds to write individually, then 90 seconds to discuss with a partner, then share out. Focus the debrief on what the parallel reveals versus what it hides.

0:43 to 0:45: Exit Ticket Students write one sentence completing this prompt: "The Sound Dues parallel suggests that the Hormuz crisis will resolve through __________, but this prediction might be wrong because __________." Collect as a formative assessment.

---

Extension Activity

"The Copenhagen Convention of 2026": A Diplomatic Simulation and Policy Brief

This two to three day project asks students to simulate the negotiation that ended the Sound Dues and apply its logic to the Strait of Hormuz.

Day 1: Research and Role Assignment Assign students to represent one of the following stakeholders: the United States, Iran, China, India, the European Union, Saudi Arabia, and a coalition of smaller shipping nations. Each group researches their assigned party's economic dependence on Hormuz shipping, their legal position on the blockade, and their preferred resolution.

Day 2: Negotiation Simulation Groups negotiate a fictional "Hormuz Convention" modeled on the 1857 Copenhagen Convention. They must agree on: who pays, how much, what legal principle is established, and what verification mechanism ensures compliance. Each group must make at least one concession.

Day 3: Policy Brief Each student writes a 400 to 600 word policy brief addressed to their assigned party's head of government. The brief must: summarize the negotiated outcome, explain why it is better than continued military confrontation, and cite at least one historical precedent (the Sound Dues or another chokepoint dispute) as supporting evidence.

Assessment: Grade on quality of historical evidence used, clarity of the argument, and accuracy of the stakeholder's interests as represented.

---

Primary Source Connections

1. The Copenhagen Convention (1857)

1. Sound Dues Registers (Øresundstoldregnskaber), 1497–1857

1. UN Convention on the Law of the Sea (UNCLOS), Article 38: Right of Transit Passage (1982)

1. Kronborg Castle: Historical Engravings and Maps (16th–17th century)

---

Standards Alignment

C3 Framework

• Dimension 1 (Developing Questions): This lesson supports the inquiry arc by asking students to generate and refine compelling questions about geographic power, economic coercion, and the resolution of international disputes. The anticipation questions and parallel analysis questions are designed to move students from surface curiosity ("why did Denmark charge a toll?") to disciplinary inquiry ("under what conditions do chokepoint disputes resolve through negotiation rather than force?").

• Dimension 2 (Applying Concepts): The lesson draws on disciplinary concepts from all four C3 social studies domains. From history: causation, continuity and change over time, and contextualization. From economics: opportunity cost, trade interdependence, and the logic of rent-seeking behavior. From civics: the legal definition of blockade, freedom of navigation, and the authority of international law. From geography: the concept of chokepoints, spatial thinking about strategic waterways, and the relationship between physical geography and political power.

• Dimension 3 (Evaluating Sources): The story itself models source evaluation by presenting both pro-blockade and anti-blockade arguments and asking students to assess their relative weight. The primary source connections require students to work with treaty texts, administrative records, and legal documents of different types and periods, evaluating each for its purpose, audience, and limitations. The parallel analysis questions explicitly ask students to evaluate the historical analogy as a form of evidence, identifying where it illuminates and where it misleads.

• Dimension 4 (Communicating Conclusions): Multiple activities require students to construct and communicate evidence-based arguments. The exit ticket requires a written claim with a counterargument. The structured discussion requires oral argumentation with textual evidence. The extension activity requires a formal policy brief addressed to a specific audience, using historical precedent as supporting evidence.

---

AP Alignment

• AP World History: Modern, Key Concept 4.1 (Globalizing Networks of Exchange): The Sound Dues are a direct case study in how states extracted revenue from expanding global trade networks, and how commercial interests eventually forced the liberalization of chokepoints. This connects to broader themes of trade route control, mercantilism, and the transition to free trade ideology in the nineteenth century.

• AP European History, Key Concept 1.5 (Interaction of Europe and the World) and Key Concept 2.1 (Commercial Capitalism): The Sound Dues illustrate the intersection of European state-building, commercial capitalism, and the competition for control of trade routes that defined early modern European history. The 1857 resolution connects to the broader nineteenth-century shift toward free trade liberalism associated with the repeal of the Corn Laws and the Cobden-Chevalier Treaty.

• AP US History, Key Concept 9.3 (The Contested Meaning of Freedom) and Thematic Focus on America in the World (WOR): The Hormuz blockade raises questions about the scope of American military and economic power, the tension between national interest and international law, and the United States' self-appointed role as guarantor of freedom of navigation. These connect directly to the AP US History thematic focus on America's relationship with the world and the recurring tension between unilateral action and multilateral frameworks.