diff --git a/src/Controllers/participant.controller.ts b/src/Controllers/participant.controller.ts
index 2e0a56a..ee53b5e 100644
--- a/src/Controllers/participant.controller.ts
+++ b/src/Controllers/participant.controller.ts
@@ -1,5 +1,5 @@
 import prisma from "../lib/prisma";
-import { z } from "zod";
+import { string, z } from "zod";
 import { Request, Response } from "express";
 import { DataType, generateError, generateInvalidBodyError } from "./common";
 import { Prisma } from "@prisma/client";
@@ -10,7 +10,7 @@ import { requireLeaderOfTeam } from "../Middleware/auth/teamleaderAuth";
 const InitialParticipant = z.object({
   firstName: z.string(),
   lastName: z.string(),
-  groupPid: z.string().uuid(),
+  groupPid: z.string().min(1).uuid(),
 });
 
 const ParticipantBody = InitialParticipant.extend({ teamPid: z.string().uuid() });
@@ -58,6 +58,21 @@ export const createParticipant = async (req: Request, res: Response) => {
   }
 
   try {
+    const discipline = await prisma.team.findUnique({
+      where: { pid: body.teamPid },
+      select: { discipline: true }
+    });
+
+    const maxteamsize = discipline?.discipline.maxTeamSize;
+
+    const userCount = await prisma.participant.count({
+      where: { team: { pid: body.teamPid } }
+    });
+
+    if (maxteamsize == userCount) {
+      return res.status(418).json({ type: "error", payload: "The team has reached the limit of participants!" });
+    }
+
     const participant = await prisma.participant.create({
       data: {
         firstName: body.firstName,
@@ -69,10 +84,7 @@ export const createParticipant = async (req: Request, res: Response) => {
       select: returnedParticipant,
     });
 
-    return res.status(201).json({
-      type: "success",
-      payload: { participant },
-    });
+    return res.status(201).json({ type: "success", payload: { participant }, });
   } catch (e) {
     if (e instanceof PrismaClientKnownRequestError && e.code === "P2025") {
       return res
@@ -86,9 +98,10 @@ export const createParticipant = async (req: Request, res: Response) => {
 // at: PATCH api/participants/:pid/
 export const updateParticipant = async (req: Request<{ pid: string }>, res: Response) => {
   const { pid } = req.params;
+  const teamPid = await getTeamPidByParticipantPid(pid);
 
   if (req.teamleader?.isAuthenticated) {
-    requireLeaderOfTeam(req.teamleader, pid);
+    requireLeaderOfTeam(req.teamleader, teamPid);
   }
 
   const result = InitialParticipant.partial().safeParse(req.body);
@@ -135,9 +148,10 @@ export const updateParticipant = async (req: Request<{ pid: string }>, res: Resp
 // at: DELETE api/participants/:pid/
 export const deleteParticipant = async (req: Request<{ pid: string }>, res: Response) => {
   const { pid } = req.params;
+  const teamPid = await getTeamPidByParticipantPid(pid);
 
   if (req.teamleader?.isAuthenticated) {
-    requireLeaderOfTeam(req.teamleader, pid);
+    requireLeaderOfTeam(req.teamleader, teamPid);
   }
 
   try {
@@ -152,3 +166,16 @@ export const deleteParticipant = async (req: Request<{ pid: string }>, res: Resp
     throw e;
   }
 };
+
+export const getTeamPidByParticipantPid = async function (partPid: string) {
+  const participant = await prisma.participant.findUnique({
+    where: { pid: partPid },
+    select: { team: { select: { pid: true } } }
+  });
+
+  if (!participant) {
+    throw new NotFoundError("participant", partPid);
+  }
+
+  return participant.team.pid;
+}
diff --git a/src/Controllers/role.controller.ts b/src/Controllers/role.controller.ts
index 294db70..250fa97 100644
--- a/src/Controllers/role.controller.ts
+++ b/src/Controllers/role.controller.ts
@@ -5,6 +5,7 @@ import prisma from "../lib/prisma";
 import { requireLeaderOfTeam, requireResponsibleForParticipant } from "../Middleware/auth/teamleaderAuth";
 import NotFoundError from "../Middleware/error/NotFoundError";
 import { createInsufficientPermissionsError, DataType, generateInvalidBodyError } from "./common";
+import { getTeamPidByParticipantPid } from "./participant.controller";
 
 require("express-async-errors");
 
@@ -53,15 +54,15 @@ export async function createRolesForTeam(teamPid: string) {
   return roles.count;
 }
 
-export async function getRolesForTeam(req: Request<{ teamPid: string }>, res: Response) {
-  const teamPid = req.params.teamPid;
+export async function getRolesForTeam(req: Request<{ pid: string }>, res: Response) {
+  const pid = req.params.pid;
 
   if (req.teamleader?.isAuthenticated) {
-    requireLeaderOfTeam(req.teamleader, teamPid);
+    requireLeaderOfTeam(req.teamleader, pid);
   }
 
   const roles = await prisma.role.findMany({
-    where: { team: { pid: teamPid } },
+    where: { team: { pid } },
     select: {
       pid: true,
       score: true,
@@ -80,16 +81,13 @@ export async function getRolesForTeam(req: Request<{ teamPid: string }>, res: Re
 
 const AssignParticipantToRoleBody = z.object({
   participantPid: z.string().uuid(),
+  teamPid: z.string().uuid(),
 });
 
 // requires: auth(leader of the team)
 export async function assignParticipantToRole(req: Request<{ pid: string }>, res: Response) {
   const { pid } = req.params;
 
-  if (req.teamleader?.isAuthenticated) {
-    requireLeaderOfTeam(req.teamleader, pid);
-  }
-
   const zBody = AssignParticipantToRoleBody.safeParse(req.body);
 
   if (zBody.success === false) {
@@ -97,6 +95,11 @@ export async function assignParticipantToRole(req: Request<{ pid: string }>, res
   }
 
   const { participantPid } = zBody.data;
+  const teamPid = await getTeamPidByParticipantPid(pid);
+
+  if (req.teamleader?.isAuthenticated) {
+    requireLeaderOfTeam(req.teamleader, teamPid);
+  }
 
   const schema = await prisma.role.findFirst({
     where: { pid, team: { participants: { some: { pid: participantPid } } } },
diff --git a/src/Controllers/team.controller.ts b/src/Controllers/team.controller.ts
index 88d1271..15a8044 100644
--- a/src/Controllers/team.controller.ts
+++ b/src/Controllers/team.controller.ts
@@ -32,7 +32,7 @@ export const getTeams = async (req: Request, res: Response) => {
   res.status(200).json({ type: "success", payload: { teams } });
 };
 
-export const getTeam = async (req: Request, res: Response) => {
+export const getTeam = async (req: Request<{ pid: string }>, res: Response) => {
   const { pid } = req.params;
 
   if (req.teamleader?.isAuthenticated) {
@@ -44,6 +44,10 @@ export const getTeam = async (req: Request, res: Response) => {
     select: basicTeam,
   });
 
+  if (!team) {
+    throw new NotFoundError("team", pid);
+  }
+
   res.status(200).json({ type: "success", payload: { team } });
 };
 
diff --git a/src/Routes/role.routes.ts b/src/Routes/role.routes.ts
index 6ca39ae..b23d118 100644
--- a/src/Routes/role.routes.ts
+++ b/src/Routes/role.routes.ts
@@ -4,17 +4,10 @@ import { requireConfiguredAuthentication } from "../Middleware/auth/auth";
 
 const router = Express.Router();
 
-//TO DO: maybe transfer getRolesForTeam to team router -> Seconded
-router.get<"team/:teamPid/", { teamPid: string }>(
-  "team/:teamPid/",
-  requireConfiguredAuthentication({ optional: false, type: { admin: true, teamleader: true } }),
-  getRolesForTeam
-);
-
 router.put<"/:pid/participant", { pid: string }>(
   "/:pid/participant",
   requireConfiguredAuthentication({ optional: false, type: { admin: true, teamleader: true } }),
   assignParticipantToRole
 );
 
-export default router;
+export default router;
\ No newline at end of file
diff --git a/src/Routes/team.routes.ts b/src/Routes/team.routes.ts
index b419c1c..a49789a 100644
--- a/src/Routes/team.routes.ts
+++ b/src/Routes/team.routes.ts
@@ -1,12 +1,13 @@
 import express from "express";
 import { requireConfiguredAuthentication } from "../Middleware/auth/auth";
 import { deleteTeam, getTeam, getTeams, updateTeam } from "../Controllers/team.controller";
+import { getRolesForTeam } from "../Controllers/role.controller";
 
 const router = express.Router();
 
 router.get("/", requireConfiguredAuthentication({ type: "admin", optional: false }), getTeams);
-router.get(
-  "/:id",
+router.get<"/:pid/", { pid: string }>(
+  "/:pid/",
   requireConfiguredAuthentication({ optional: false, type: { admin: true, teamleader: true } }),
   getTeam
 );
@@ -22,4 +23,10 @@ router.delete<"/:pid/", { pid: string }>(
   deleteTeam
 );
 
+router.get<"/:pid/roles", { pid: string }>(
+  "/:pid/roles",
+  requireConfiguredAuthentication({ optional: false, type: { admin: true, teamleader: true } }),
+  getRolesForTeam
+);
+
 export default router;