diff --git a/src/parser/GspnParser.cpp b/src/parser/GspnParser.cpp
index ded4f7cf1..a863ffb1a 100644
--- a/src/parser/GspnParser.cpp
+++ b/src/parser/GspnParser.cpp
@@ -1,8 +1,221 @@
+#include <string>
+#include <memory>
+#include <iosfwd>
+#include <bitset>
 #include "src/parser/GspnParser.h"
 
 storm::gspn::GSPN storm::parser::GspnParser::parse(const std::string &filename) {
+    // initialize xerces
+    try {
+        xercesc::XMLPlatformUtils::Initialize();
+    }
+    catch (const xercesc::XMLException& toCatch) {
+        // TODO do something
+    }
 
-    //xercesc::XercesDOMParser;
 
-    return storm::gspn::GSPN();
+
+    auto parser = new xercesc::XercesDOMParser();
+    parser->setValidationScheme(xercesc::XercesDOMParser::Val_Always);
+    parser->setDoNamespaces(false);
+    parser->setDoSchema(false);
+    parser->setLoadExternalDTD(false);
+    parser->setIncludeIgnorableWhitespace(false);
+    //parser->loadGrammar(source, type);
+
+    auto errHandler = (xercesc::ErrorHandler*) new xercesc::HandlerBase();
+    parser->setErrorHandler(errHandler);
+
+    try {
+        parser->parse(filename.c_str());
+    }
+    catch (const xercesc::XMLException& toCatch) {
+        auto message = xercesc::XMLString::transcode(toCatch.getMessage());
+        std::cout << "Exception message is: \n"
+        << message << "\n";
+        xercesc::XMLString::release(&message);
+    }
+    catch (const xercesc::DOMException& toCatch) {
+        auto message = xercesc::XMLString::transcode(toCatch.msg);
+        std::cout << "Exception message is: \n"
+        << message << "\n";
+        xercesc::XMLString::release(&message);
+    }
+    catch (...) {
+        std::cout << "Unexpected Exception \n" ;
+    }
+
+
+    parser->getDocument()->normalizeDocument();
+    xercesc::DOMElement* elementRoot = parser->getDocument()->getDocumentElement();
+    if (getName(elementRoot).compare("pnml") != 0) {
+        std::cout << "expected: pnml" << std::endl;
+        std::cout << "found: " << XMLtoString(elementRoot->getTagName()) << std::endl;
+        // TODO error
+    }
+    parsePNML(elementRoot);
+
+    delete parser;
+    delete errHandler;
+
+
+    // clean up
+    xercesc::XMLPlatformUtils::Terminate();
+
+    return gspn;
+}
+
+std::string storm::parser::GspnParser::XMLtoString(const XMLCh *xmlString) {
+    char* tmp = xercesc::XMLString::transcode(xmlString);
+    auto result = std::string(tmp);
+    delete tmp;
+    return result;
+}
+
+void storm::parser::GspnParser::parsePNML(xercesc::DOMElement *element) {
+    std::cout << "pnml" << std::endl;
+    for (uint64_t i = 0; i < element->getChildNodes()->getLength(); ++i) {
+        auto child = element->getChildNodes()->item(i);
+        auto name = getName(child);
+        if (name.compare("net") == 0) {
+            parseNet(child);
+        } else if (std::all_of(name.begin(), name.end(), isspace)) {
+            // TODO remove after adding DTD
+        } else {
+            std::cout << "unkown child: " << name << std::endl;
+        }
+    }
+}
+
+void storm::parser::GspnParser::parseNet(xercesc::DOMNode* node) {
+    std::cout << "net" << std::endl;
+    for (uint64_t i = 0; i < node->getChildNodes()->getLength(); ++i) {
+        auto child = node->getChildNodes()->item(i);
+        auto name = getName(child);
+        if (name.compare("page") == 0) {
+            parsePage(child);
+        } else if (name.compare("place") == 0) {
+            parsePlace(child);
+        } else if (name.compare("transition") == 0) {
+            parseTransition(child);
+        } else if (name.compare("arc") == 0) {
+            parseArc(child);
+        } else if (std::all_of(name.begin(), name.end(), isspace)) {
+            // TODO remove after adding DTD
+        } else if (name.compare("name") == 0) {
+            // ignore these tags
+        } else {
+            std::cout << "unkown child: " << name << std::endl;
+        }
+    }
+}
+
+void storm::parser::GspnParser::parsePage(xercesc::DOMNode *node) {
+    std::cout << "page" << std::endl;
+    for (uint64_t i = 0; i < node->getChildNodes()->getLength(); ++i) {
+        auto child = node->getChildNodes()->item(i);
+        auto name = getName(child);
+        if (name.compare("place") == 0) {
+            parsePlace(child);
+        } else if (name.compare("transition") == 0) {
+            parseTransition(child);
+        } else if (name.compare("arc") == 0) {
+            parseArc(child);
+        } else if (std::all_of(name.begin(), name.end(), isspace)) {
+            // TODO remove after adding DTD
+        } else {
+            std::cout << "unkown child: " << name << std::endl;
+        }
+    }
+}
+
+void storm::parser::GspnParser::parsePlace(xercesc::DOMNode *node) {
+    std::cout << "place" << std::endl;
+    uint64_t place;
+    for (uint64_t i = 0; i < node->getAttributes()->getLength(); ++i) {
+        auto attr = node->getAttributes()->item(i);
+        auto name = getName(attr);
+        if (name.compare("id") == 0) {
+            place = addNewPlace(XMLtoString(attr->getNodeValue()));
+        } else {
+            std::cout << "unkown attr.: " << name << std::endl;
+        }
+    }
+
+    //redo
+    for (uint64_t i = 0; i < node->getChildNodes()->getLength(); ++i) {
+        auto child = node->getChildNodes()->item(i);
+        auto name = getName(child);
+        if (name.compare("initialMarking") == 0) {
+            auto tokens = parseInitialMarking(child);
+            gspn.setInitialTokens(place, tokens);
+        } else if (std::all_of(name.begin(), name.end(), isspace)) {
+            // TODO remove after adding DTD
+        } else if (name.compare("name") == 0 ||
+                  name.compare("graphics") == 0) {
+            // ignore these tags
+        } else {
+            std::cout << "unkown child: " << name << std::endl;
+        }
+    }
+}
+
+void storm::parser::GspnParser::parseTransition(xercesc::DOMNode *node) {
+    //std::cout << "transition" << std::endl; // TODO
+    bool timed = false;
+    //value for the rate
+
+}
+
+void storm::parser::GspnParser::parseArc(xercesc::DOMNode *node) {
+    //std::cout << "arc" << std::endl; // TODO
+}
+
+std::string storm::parser::GspnParser::getName(xercesc::DOMNode *node) {
+    switch (node->getNodeType()) {
+        case xercesc::DOMNode::NodeType::ELEMENT_NODE: {
+            auto elementNode = (xercesc::DOMElement *) node;
+            return XMLtoString(elementNode->getTagName());
+        }
+        case xercesc::DOMNode::NodeType::TEXT_NODE: {
+            return XMLtoString(node->getNodeValue());
+        }
+        case xercesc::DOMNode::NodeType::ATTRIBUTE_NODE: {
+            return XMLtoString(node->getNodeName());
+        }
+        default: {
+            std::cout << "unknown NodeType: " << node->getNodeType() << std::endl;
+            return "";
+        }
+    }
+}
+
+uint64_t storm::parser::GspnParser::addNewPlace(std::string id) {
+    auto place = newNode;
+    ++newNode;
+    stringToState[id] = place;// TODO check whether the id is already in the map
+    return place;
+}
+
+uint64_t storm::parser::GspnParser::parseInitialMarking(xercesc::DOMNode *node) {
+    std::cout << "initialMarking" << std::endl;
+    uint64_t result= 0;
+    for (uint64_t i = 0; i < node->getChildNodes()->getLength(); ++i) {
+        auto child = node->getChildNodes()->item(i);
+        auto name = getName(child);
+        if (name.compare("text") == 0) {
+            result = std::stoull(getName(child->getFirstChild()));
+        } else if (name.compare("value") == 0) {
+            auto value = getName(child->getFirstChild());
+            value.substr(std::string("Default,").length()-1);
+            result = std::stoull(value);
+        } else if (std::all_of(name.begin(), name.end(), isspace)) {
+            // TODO remove after adding DTD
+        } else if (name.compare("graphics") == 0) {
+            // ignore these tags
+        } else {
+            std::cout << "unkown child: " << name << std::endl;
+        }
+    }
+    return result;
 }
diff --git a/src/parser/GspnParser.h b/src/parser/GspnParser.h
index 4675f80f4..f66d437b0 100644
--- a/src/parser/GspnParser.h
+++ b/src/parser/GspnParser.h
@@ -1,8 +1,13 @@
 #ifndef STORM_GSPNPARSER_H
 #define STORM_GSPNPARSER_H
 
+#include <iostream>
 #include <string>
 #include <xercesc/parsers/XercesDOMParser.hpp>
+#include <xercesc/dom/DOM.hpp>
+#include <xercesc/sax/HandlerBase.hpp>
+#include <xercesc/util/XMLString.hpp>
+#include <xercesc/util/PlatformUtils.hpp>
 #include "src/storage/gspn/GSPN.h"
 
 namespace storm {
@@ -16,8 +21,89 @@ namespace storm {
              * @param filename The name of the file to parse
              * @return The resulting GSPN.
              */
-            static storm::gspn::GSPN parse(std::string const& filename);
+            storm::gspn::GSPN parse(std::string const& filename);
+
+            /*!
+             * Transforms the given XML String to a normal string.
+             *
+             * @param xmlString The given String in the XML format
+             * @return The corresponding standard string.
+             */
+            static std::string XMLtoString(const XMLCh* xmlString);
         private:
+            // maps the original name of the state to its numerical representation
+            std::map<std::string,uint64_t> stringToState;
+
+            // the constructed gspn
+            storm::gspn::GSPN gspn;
+
+            // has the new id for a new node
+            uint64_t newNode;
+
+            /*!
+             * Parses the root element (TagName = pnml).
+             *
+             * @param element The root element.
+             */
+            void parsePNML(xercesc::DOMElement* element);
+
+            /*!
+             * Parses a net node (NodeName = net).
+             *
+             * @param node The net node.
+             */
+            void parseNet(xercesc::DOMNode* node);
+
+            /*!
+             * Parses a page node (NodeName = page).
+             *
+             * @param node The page node.
+a            */
+            void parsePage(xercesc::DOMNode* node);
+
+            /*!
+             * Parses a place node (NodeName = place).
+             *
+             * @param node The place node.
+             */
+            void parsePlace(xercesc::DOMNode* node);
+
+            /*!
+             * Parses a transition node (NodeName = transition).
+             *
+             * @param node The transition node.
+             */
+            void parseTransition(xercesc::DOMNode* node);
+
+            /*!
+             * Parses an arc node (NodeName = arc).
+             *
+             * @param node The arc node.
+             */
+            void parseArc(xercesc::DOMNode* node);
+
+            /*!
+             * Parses an initial marking Node (Nodename = initialMarking)
+             *
+             * @param node the initial marking node.
+             * @return The number of tokens.
+             */
+            uint64_t parseInitialMarking(xercesc::DOMNode* node);
+
+            /*!
+             * Adds a new entry in the mapping from string to places.
+             *
+             * @param id The string id for the new place
+             * @return The new place.
+             */
+            uint64_t addNewPlace(std::string id);
+
+            /*!
+             * Gives the name of the current node.
+             * @param node Current node.
+             * @return The name.
+             */
+            std::string getName(xercesc::DOMNode* node);
         };
     }
 }
diff --git a/src/storage/gspn/GSPN.cpp b/src/storage/gspn/GSPN.cpp
index f32dded64..0ac6b1c77 100644
--- a/src/storage/gspn/GSPN.cpp
+++ b/src/storage/gspn/GSPN.cpp
@@ -1,4 +1,11 @@
 #include "src/storage/gspn/GSPN.h"
 
 storm::gspn::GSPN::GSPN() : initialMarking(0, 0) {
-}
\ No newline at end of file
+}
+
+void storm::gspn::GSPN::setInitialTokens(uint64_t place, uint64_t token) {
+    if (initialMarking.getMaxNumberOfTokens() < token) {
+        initialMarking.setMaxNumberOfTokens(token);
+    }
+    initialMarking.setNumberOfTokensAt(place, token);
+}
diff --git a/src/storage/gspn/GSPN.h b/src/storage/gspn/GSPN.h
index 711b69140..7f6329eca 100644
--- a/src/storage/gspn/GSPN.h
+++ b/src/storage/gspn/GSPN.h
@@ -19,6 +19,14 @@ namespace storm {
              * The empty constructor creates an GSPN without transition and places
              */
             GSPN();
+
+            /*!
+             * Set the number of tokens for a given place.
+             *
+             * @param place
+             * @param token
+             */
+            void setInitialTokens(uint64_t place, uint64_t token);
         private:
             // set containing all immediate transitions
             std::vector<storm::gspn::ImmediateTransition<WeightType>> immediateTransitions;
diff --git a/src/storage/gspn/Marking.cpp b/src/storage/gspn/Marking.cpp
index e17c3d8df..4d0763f6d 100644
--- a/src/storage/gspn/Marking.cpp
+++ b/src/storage/gspn/Marking.cpp
@@ -6,7 +6,7 @@ namespace storm {
             this->numberOfPlaces = numberOfPlaces;
             this->maxNumberOfTokens = maxNumberOfTokens;
 
-            this->numberOfBits = std::floor(std::log2(maxNumberOfTokens)) + 1;
+            this->numberOfBits = calculateNumberOfBits(maxNumberOfTokens);
             this->marking = storm::storage::BitVector(numberOfBits * numberOfPlaces);
         }
 
@@ -19,7 +19,7 @@ namespace storm {
         }
 
         void Marking::setNumberOfTokensAt(uint_fast64_t place, uint_fast64_t numberOfTokens) {
-            //TODO check range (place < getNumberOfPlaces(), numberOfTokens < getMaxNumberOfTokens())
+            // TODO check range (place < getNumberOfPlaces(), numberOfTokens < getMaxNumberOfTokens())
             for (uint_fast64_t i = place * numberOfBits; i <(place * numberOfBits) + numberOfBits; ++i) {
                 if (numberOfTokens % 2 == 0) {
                     marking.set(i, false);
@@ -41,11 +41,65 @@ namespace storm {
         }
 
         bool Marking::setNumberOfPlaces(uint_fast64_t numberOfPlaces) {
-            return false;
+            if (numberOfPlaces == this->numberOfPlaces) {
+                return true;
+            }
+            if (numberOfPlaces > this->numberOfPlaces) {
+                marking.resize(numberOfPlaces * numberOfBits);
+                return true;
+            } else {
+                auto diff = this->numberOfPlaces - numberOfPlaces;
+                for (uint64_t i = 0; i < diff; ++i) {
+                    if (getNumberOfTokensAt(numberOfPlaces-1-i) != 0) {
+                        // TODO error
+                        return false;
+                    }
+                }
+                marking.resize(numberOfPlaces * numberOfBits);
+                return true;
+            }
         }
 
         bool Marking::setMaxNumberOfTokens(uint_fast64_t maxNumberOfTokens) {
-            return false;
+            for (uint64_t i = 0; i < getNumberOfPlaces(); ++i) {
+                if (getNumberOfTokensAt(i) > maxNumberOfTokens) {
+                    return false;
+                }
+            }
+
+            if (maxNumberOfTokens == getMaxNumberOfTokens()) {
+                return true;
+            }
+
+            uint_fast64_t newNumberOfBits = calculateNumberOfBits(maxNumberOfTokens);
+            if (maxNumberOfTokens < getMaxNumberOfTokens()) {
+                for (uint_fast64_t i = 0; i < getNumberOfPlaces(); ++i) {
+                    for (uint_fast64_t j = 0; j < numberOfBits; ++j) {
+                        marking.set(i*newNumberOfBits + j , marking.get(i*numberOfBits + j));
+                    }
+                }
+                marking.resize(getNumberOfPlaces() * newNumberOfBits);
+            } else {
+                marking.resize(getNumberOfPlaces() * newNumberOfBits);
+                for (uint_fast64_t i = getNumberOfPlaces()-1; i >= 0; --i) {
+                    for (uint_fast64_t j = numberOfBits-1; j >= 0; --j) {
+                        for (uint_fast64_t diff = 0; diff < newNumberOfBits-numberOfBits; ++diff) {
+                            marking.set(i*newNumberOfBits+j+diff+1, 0);
+                        }
+                        marking.set(i*newNumberOfBits+j, marking.get(i*numberOfBits+j));
+                    }
+                }
+            }
+            numberOfBits = newNumberOfBits;
+            return true;
+        }
+
+        void Marking::incNumberOfPlaces() {
+            setNumberOfPlaces(getNumberOfPlaces()+1);
+        }
+
+        uint_fast64_t Marking::calculateNumberOfBits(uint_fast64_t maxNumber) {
+            return std::floor(std::log2(maxNumber)) + 1;
         }
     }
 }
\ No newline at end of file
diff --git a/src/storage/gspn/Marking.h b/src/storage/gspn/Marking.h
index 8f5e1400c..5d312c88c 100644
--- a/src/storage/gspn/Marking.h
+++ b/src/storage/gspn/Marking.h
@@ -58,6 +58,11 @@ namespace storm {
              */
             bool setNumberOfPlaces(uint_fast64_t numberOfPlaces);
 
+            /*!
+             * Increases the number of places by one.
+             */
+            void incNumberOfPlaces();
+
             /*!
              *
              */
@@ -74,6 +79,14 @@ namespace storm {
 
             // number of bits which are needed to store the tokens for one place
             uint_fast64_t numberOfBits;
+
+            /*!
+             * Calculates the number of bits needed to store at least the given number.
+             *
+             * @param maxNumber The maximal value which can be stored
+             * @return The number of bits needed.
+             */
+            uint_fast64_t calculateNumberOfBits(uint_fast64_t maxNumber);
         };
     }
 }
diff --git a/src/storm-gspn.cpp b/src/storm-gspn.cpp
index 8cb7211c4..450d57652 100644
--- a/src/storm-gspn.cpp
+++ b/src/storm-gspn.cpp
@@ -16,7 +16,8 @@ int main(const int argc, const char** argv) {
         storm::utility::setUp();
 
         // Parse GSPN from xml
-        storm::gspn::GSPN gspn = storm::parser::GspnParser::parse(argv[1]);
+        auto parser = storm::parser::GspnParser();
+        auto gspn = parser.parse(argv[1]);
 
         // Construct MA